Irish derby headlines the show
The pick of the round must be the sell-out Irish derby, Leinster versus Munster, in Dublin on Saturday.
The two teams currently occupy the home play-off slots, but Munster must know that any slip up in Dublin could see third-placed Ulster overtake them in the search for that end-of-season home advantage.
The game at Scotstoun on Friday is also critical to the play-offs; Glasgow Warriors currently sit in 5th place in the table just four points behind their opponents, Ospreys, but with two games in hand and a better winning record.
Should they beat the Welshmen, Glasgow will take over their spot in the play-off zone with the added advantage of an extra 10 points to play for to consolidate their position.
Sunday's game, whilst not directly affecting the play-off zone, does have implications in the table - Connacht's run of four successive victories has lifted them up five places to seventh and they travel to Scarlets in the knowledge that a win, depending on the scoreline, could see them reside in the top half of the table for the first time since the opening round this season.
We look at all the Round 18 games!
Friday, March 28
Glasgow Warriors v Ospreys
(Scotstoun Stadium - Kick-off: 19.35; 19.35 GMT)
Glasgow Warriors have won their last two matches at Scotstoun, but have not managed to score more than two tries in a game at the venue in any match this season.
The most recent Pro12 fixture featuring the Warriors to yield a try bonus point for either side came when the Ospreys last visited Scotstoun in Round 21 last season.
Ospreys have slipped to four straight away defeats in all competitions and have not won outside of Wales since a trip to Connacht in the Pro12 in September.
The Welshmen's only victory in their last eight visits to Scotland since 2009 came when they beat Edinburgh 15-14 at Murrayfield in February 2012.
Glasgow have won their last five contests with Ospreys whilst the Welsh region's most recent victory in Glasgow came on a trip to Firhill in September 2009.
Glasgow: 15 Peter Murchie, 14 Tommy Seymour, 13 Alex Dunbar, 12 Finn Russell, 11 Niko Matawalu, 10 Duncan Weir, 9 Greig Laidlaw (captain), 8 Josh Strauss, 7 Chris Fusaro, 6 Rob Harley, 5 Jonny Gray, 4 Leone Nakawara, 3 Jon Welsh, 2 Pat MacArthur, 1 Gordon Reid.
Replacements: 16 Dougie Hall, 17 Jerry Yanuyanutawa, 18 Moray Low, 19 Ryan Wilson, 20 Tyrone Holmes, 21 Ruaridh Jackson, 22 Richie Vernon, 23 Sean Maitland.
Ospreys: 15 Sam Davies, 14 Jeff Hassler, 13 Hanno Dirksen, 12 Jonathan Spratt, 11 Aisea Natoga, 10 Dan Biggar, 9 Rhys Webb, 8 Dan Baker, 7 Justin Tipuric, 6 Sam Lewis, 5 Alun Wyn Jones (captain), 4 James King, 3 Aaron Jarvis, 2 Scott Baldwin, 1 Duncan Jones.
Replacements: 16 Scott Otten, 17 Nicky Smith, 18 Adam Jones, 19 Tyler Ardron, 20 Morgan Allen, 21 Joe Bearman, 22 Tom Habberfield, 23 Richard Fussell.
Referee: John Lacey
Assistant referees: Peter Allan, TBC
Saturday, March 29
Zebre v Newport Gwent Dragons
(Stadio XXV April - Kick-off: 16.00; 15.00 GMT)
Zebre's only victory in their last five Pro12 matches came against Cardiff Blues in Parma two rounds ago.
Zebre are attempting to win back-to-back home games for the first time in their history.
Newport Gwent Dragons have also won only one of their last five Pro12 contests: 24-23 at home to Glasgow in Round 15.
The Dragons only away victory in the competition since they visited Zebre last year was when they beat Glasgow at Scotstoun on 22nd November.
The Welsh region have won all three previous encounters with Zebre but only won by the narrowest of margins, 14-13 on their only previous visit to Stadio XXV Aprile in round 16 last season.
Zebre: 15 Guglielmo Palazzani, 14 Leonardo Sarto, 13 Tommaso Iannone, 12 Gonzalo Garcia, 11 Dion Berryman,,10 Luciano Orquera, 9 Brendon Leonard, 8 Samuela Vunisa, 7 Andries van Schalkwyk, 6 Filippo Ferrarini, 5 Marco Bortolami (captain), 4 Quintin Geldenhuys, 3 David Ryan, 2 Davide Giazzon, 1 Salvatore Perugini.
Replacements: 16 Tommaso D'apice, 17 Matias Aguero, 18 Dario Chistolini, 19 Emiliano Caffini, 20 Filippo Cristiano, 21 David Odiete, 22 Giovanbattista Venditti, 23 Kameli Ratuvou.
Newport Gwent Dragons: 15 Dan Evans, 14 Tom Prydie, 13 Pat Leach, 12 Ashley Smith, 11 Will Harries, 10 Jason Tovey, 9 Richie Rees, 8 Taulupe Faletau. 7 Nic Cudd, 6 Lewis Evans, 5 Matthew Screech, 4 Andrew Coombs (captain), 3 Duncan Bell, 2 Elliot Dee, 1 Phil Price.
Replacements: 16 Sam Parry, 17 Bruce Douglas, 18 Nathan Buck, 19 Cory Hill, 20 Jevon Groves, 21 Wayne Evans, 22 Jack Dixon, 23 Hallam Amos.
Referee: Peter Fitzgibbon
Assistant referees: Matteo Liperini, Elia Rizzon
TMO: Carlo Damasco
Benetton Treviso v Edinburgh
(Stadio Monigo - Kick-off: 19.00; 18.00 GMT)
Benetton Treviso have lost their last eight matches in all tournaments and have not scored a try in the Pro12 for 266 minutes, since Leonardo Sarto crossed against Ospreys on 16th February - this is still a long way short of the league record though, which Llanelli RFC hold at 350 minutes.
Edinburgh's only victory in their last five matches in all tournaments came against Ospreys at Meggetland on 28th February.
The Scotsmen have picked up just two league points away from home this season, both losing bonus points, in their last two matches at Connacht and at Scarlets. Edinburgh have won three of their last four matches against Italian opposition.
The two sides have met on seven previous occasions with the Scotsmen having the slight edge by four wins to three.
Benetton Treviso: 15 Luke McLean, 14 Ludovico Nitoglia, 13 Michele Campagnaro, 12 Alberto Sgarbi, 11 Angelo Esposito, 10 James Ambrosini, 9 Tobias Botes, 8 Robert Barbieri, 7 Marco Filippucci, 6 Manoa Vosawai, 5 Corniel Van Zyl, 4 Antonio Pavanello (captain), 3 Lorenzo Cittadini, 2 Leonardo Ghiraldini, 1 Alberto De Marchi
Replacements: 16 Giovanni Maistri, 17 Matteo Muccignat, 18 Ignacio Fernandez-Rouyet, 19 Marco Fuser, 20 Valerio Bernabò, 21 Christian Loamanu, 22 Fabio Semenzato, 23 Alberto Di Bernardo.
Edinburgh: 15 Carl Bezuidenhout, 14 Jack Cuthbert, 13 Matt Scott, 12 Andries Strauss (captain), 11 Tom Brown, 10 Harry Leonard, 9 Grayson Hart, 8 David Denton, 7 Roddy Grant, 6 Cornell Du Preez, 5 Izak van der Westhuizen, 4 Grant Gilchrist, 3 Willem Nel, 2 Ross Ford, 1 Alasdair Dickinson.
Replacements: 16 James Hilterbrand, 17 Wicus Blaauw, 18 Ewan McQuillin, 19 Ollie Atkins, 20 Tomas Leonardi, 21 Sean Kennedy, 22 Sam Beard, 23 Sam Hidalgo-Clyne.
Referee: Nigel Owens
Assistant referees: Stefano Penne, Stefano Traversi
TMO: Alan Falzone
Cardiff Blues v Ulster
(Arms Park - Kick-off: 18.30; 18.30 GMT)
Cardiff Blues have lost their last five Pro12 matches equalling their worst ever run in the competition.
The Blues only victory in their last nine fixtures with Irish provinces was 21-10 over Connacht at the Arms Park in Round Two this season.
Ulster have won their last eight matches in all tournaments although their 9-3 victory at Edinburgh on Friday was only the third time in the history of the tournament that Ulster have won a game without scoring a try.
The Ulstermen have lost on two of their last three visits to Wales whilst the Blues only victory in their last seven encounters with Ulster was 21-14 at the Arms Park in February 2012.
Cardiff Blues: 15 Dan Fish, 14 Alex Cuthbert, 13 Cory Allen, 12 Isaia Tuifua, 11 Chris Czekaj, 10 Gareth Davies, 9 Lewis Jones, 8 Robin Copeland 7 Josh Navidi, 6 Macauley Cook, 5 Filo Paulo, 4 Lou Reed, 3 Taufa'ao Filise, 2 Kristian Dacey, 1 Gethin Jenkins (captain).
Replacements: 16 Matthew Rees, 17 Thomas Davies, 18 Scott Andrews, 19 James Down, 20 Ellis Jenkins, 21 Lloyd Williams, 22 Simon Humberstone, 23 Gavin Evans.
Ulster: 15 Jared Payne, 14 Tommy Bowe, 13 Darren Cave, 12 Luke Marshall, 11 Andrew Trimble, 10 Paddy Jackson, 9 Michael Heaney, 8 Nick Williams, 7 Chris Henry, 6 Stephen Ferris, 5 Dan Tuohy , 4 Johann Muller (captain), 3 John Afoa, 2 Rob Herring, 1 Tom Court.
Replacements: 16 Niall Annett, 17 Andrew Warwick, 18 Ricky Lutton 19 Iain Henderson, 20 Robbie Diack, 21 Sean Doyle, 22 Paul Marshall, 23 Craig Gilroy.
Referee: Marius Mitrea
Assistant referees: Gwyn Morris, Sean Brickell
TMO: Gareth Simmonds
Leinster v Munster
(Aviva Stadium - Kick-off: 19.00; 19.00 GMT)
Leinster have won their last nine matches in all tournaments and have dropped only two points out of a possible thirty in their last six Pro12 fixtures.
The Leinstermen have lost on their last two visits to Aviva Stadium, but both of these games were in the European Cup, however the Leinstermen have won all twelve previous Pro12 games they have played at the venue .
Munster's only defeat in their last seven matches in all tournaments was 13-18 at the Scarlets in round 16 of the Pro12.
The Munstermen have lost on their last four visits to the home of Irish since they beat Leinster at the old Lansdowne Road in the semifinal of the European Cup in 2006.
Munster beat Leinster 19-15 at Thomond Park in round 5 and are going for a first regular season double over their fiercest rivals since 2008/09.
Leinster: 15 Rob Kearney, 14 Fergus McFadden, 13 Brian O'Driscoll, 12 Gordon D'Arcy, 11 Luke Fitzgerald, 10 Ian Madigan, 9 Eoin Reddan, 8 Jamie Heaslip (captain), 7 Shane Jennings, 6 Kevin McLaughlin, 5 Mike McCarthy, 4 Devin Toner, 3 Mike Ross, 2 Richardt Strauss, 1 Michael Bent.
Replacements: 16 Sean Cronin, 17 Jack O'Connell, 18 Ed Byrne, 19 Leo Cullen, 20 Jordi Murphy, 21 Isaac Boss, 22 Jimmy Gopperth, 23 Zane Kirchner.
Munster: 15 Felix Jones, 14 Keith Earls, 13 Casey Laulala, 12 Denis Hurley, 11 Simon Zebo, 10 Ian Keatley, 9 Conor Murray, 8 James Coughlan, 7 Tommy O'Donnell, 6 Peter O'Mahony (captain), 5 Paul O'Connell, 4 Dave Foley, 3 BJ Botha, 2 Damien Varley, 1 Dave Kilcoyne.
Replacements: 16 Duncan Casey, 17 James Cronin, 18 Alan Cotter, 19 Donncha O'Callaghan, 20 CJ Stander, 21 Duncan Williams, 22 JJ Hanrahan, 23 Gerhard van der Heever.
Referee: Pascale Gauzere
Assistant referees: David Wilkinson, Michael Black
TMO: Simon McDowell
Sunday, March 30
Scarlets v Connacht
(Parc y Scarlets - Kick-off: 14.30; 14.30 GMT)
Scarlets have slipped to successive Pro12 losses, away at Ulster and at Glasgow.
The Welshmen have won their last three matches in all tournaments at Parc y Scarlets.
Connacht have won their last four Pro12 matches and climbed from 12th to 7th spot in the table in the process.
Another victory would equal their best ever run in the competition set way back in 2002.
Scarlets have won their last four encounters against Connacht, whilst the Irish province's most recent victory in Llanelli came in October 2004 at the old Stradey Park.
Scarlets: 15 Liam Williams, 14 Kristian Phillips, 13 Jonathan Davies (captain), 12 Olly Barkley, 11 Jordan Williams, 10 Rhys Priestland, 9 Gareth Davies, 8 Sione Timani, 7 John Barclay, 6 Josh Turnbull, 5 Johan Snyman, 4 Jake Ball, 3 Rhodri Jones, 2 Ken Owens, 1 Phil John.
Replacements: 16 Emyr Phillips, 17 Rob Evans, 18 Jacobie Adriaanse, 19 Richard Kelly, 20 Lewis Rawlins, 21 Rhodri Williams, 22 Aled Thomas, 23 Gareth Maule.
Connacht: 15 Robbie Henshaw, 14 Tiernan O'Halloran, 13 Eoin Griffin, 12 Dave McSharry, 11 Fionn Carr, 10 Dan Parks, 9 Kieran Marmion, 8 Eoin McKeon, 7 Eoghan Masterson, 6 John Muldoon (captain), 5 Mick Kearney, 4 Aly Muldowney, 3 Rodney Ah You, 2 Jason Harris-Wright, 1 Denis Buckley.
Replacements: 16 Dave Heffernan, 17 Ronan Loughney, 18 Nathan White, 19 Michael Swift, 20 Andrew Browne, 21 Frank Murphy, 22 Miah Nikora, 23 Darragh Leader.
Referee: Neil Paterson
Assistant referees: Wayne Davies, Martyn Lewis
TMO: Tim Hayes