Tomas O'Leary (left) is tackled by Jonathan Thomas in Cork
Munster (3) 9
Pens: Warwick 3
Ospreys (3) 8
Paul Warwick's late penalty left the Ospreys still searching for an away win in this season's Magners League.
Sonny Parker's 74th-minute try looked set to be decisive but Munster earned an injury-time penalty after a Justin Marshall kick had been charged down.
Warwick and James Hook kicked early penalties and the Munster fly-half struck another score on 63 minutes.
After Warwick's third penalty, the Ospreys forced a last-gasp chance but Shane Williams' drop goal flew wide.
Munster made a late change to their starting line-up with coach Declan Kidney opting to rest Paul O'Callaghan "as a precaution" ahead of next weekend's Heineken Cup semi-final against Saracens.
With Ronan O'Gara already a fitness doubt, Kidney clearly felt that he didn't want his pack talisman to sustain any knocks in Saturday's relatively meaningless Magners game.
James Hook kicked the Ospreys ahead in the fourth minute but Paul Warwick quickly got Munster on terms after Shaun Payne's charge had earned a penalty.
Hook missed two further penalty chances for the Ospreys and the swirling wind also caused Munster fly-half Warwick to miss a penalty which he normally would have knocked over with ease.
Barry Murphy, Anthony Horgan and Payne all produced first-half breaks which had the Ospreys defence in trouble but the visitors defence somehow hold out.
Horgan just needed to find one of two unmarked colleagues in a three against one situation but instead he got his bearings all wrong and his pass flew harmlessly into touch.
Before the break, the Ospreys had a chance of a breakaway try but Andrew Bishop knocked-on at the crucial moment.
The Ospreys produced some pressure after the break but the Munster defence held firm.
Munster nosed ahead in the 63th minute when Warwick slotted his second penalty.
The home side should have added a try two minutes later but replacement Keith Earls appeared to go for glory himself after his superb run and the chance was lost.
Hook hit the woodwork with a long-range penalty in the 72nd minute but the Ospreys did move ahead moments later when Parker broke through several tackles to score in the right corner.
The Ospreys appeared to have matters under control in injury-time but a Marshall clearance was charged down by Marcus Horan and replacement Gareth Owen was penalised for holding on.
Warwick held his nerve to strike over the 22-metre penalty in the driving rain to restore Munster's lead.
The Ospreys still had time to produce more pressure but Shane Williams' drop goal flew inches wide.
Munster: Payne, Carney, Murphy, Lewis, Horgan, Warwick, O'Leary, Pucciariello, Sheahan, Buckley, O'Driscoll, O'Callaghan, D. Ryan, Ronan, Leamy. Replacements: Manning for Payne (70), Earls for Carney (63), Stringer for O'Leary (63), Flannery for Sheahan (63), Horan for Buckley (41), Wallace for O'Callaghan (72), Foley for Leamy (63).
Ospreys: Byrne, Vaughton, Parker, A. Bishop, S. Williams, Hook, Marshall, D Jones, Bennett, Griffiths, Gough, Evans, J Thomas, Holah, Tiatia. Replacements: Brew for Vaughton (66), Spratt for A Bishop (80), Owen for Hook (80), Shervington for Bennett (80), Millward for Griffiths (64), Bateman for Gough (80), Lewis for Holah (80).
Referee: James Jones (WRFU).