Horgan wound up a career, which began back in August 1997 against Connacht, with a try created by a brilliant offload from Kieran Lewis who has also left the Munster squad after two years of service.
Horgan has no intention of continuing to play rugby at club level and will now concentrate on his business interests, while Lewis is also planning on a career outside rugby.
Others who played against the Ospreys and are departing the Munster scene include Federico Pucciariello.
The popular Italy-capped prop arrived at the start of the 2005 season from Bourgoin and played his first game in a Munster shirt against this weekend's Heineken Cup finalists Leicester Tigers in a friendly at Welford Road.
Pucciariello, like Horgan and Lewis, will quit the rugby playing arena to concentrate on the Bio-Fuel business he is developing in his native Rosario.
But his front row colleague Frankie Sheahan, who pulled on the Munster shirt for the 163rd and final time, has agreed terms with French club Brive for next season with an option of a second.
If he takes up their offer, Sheahan could well come up against a familiar face in Timmy Ryan who is bound for Toulon.
Sheahan would undoubtedly have pushed Anthony Foley for the record as the most-capped Munster player only for a series of injuries to disrupt his run this season and in 2005/06.
He suffered a shoulder injury this season against Connacht that effectively ruled him out of action until last Friday's game.
In October 2005 he sustained a potentially career-ending neck injury against Sale Sharks in the opening Heineken Cup game at Edgeley Park.
It was a measure of the man's resilience and commitment that he battled back from that injury and although missing out on a place in the 2006 Heineken Cup final, he was in the matchday 22 for the win over Toulouse two years later.
Rua Tipoki and his family left for New Zealand on Monday. His last season with Munster was unfortunately blighted by injury, with the initial one sustained in the game against the All Blacks at Thomond Park.
One of the most popular characters in the squad, Mike Prendergast also wound up his career with an appearance from the bench on Friday that elicited a huge round of applause.
John O'Sullivan and Mark Melbourne are two more players who will bow out of the Munster squad, as will hooker Mike Essex and winger Brian Carney.
Carney was due to start Munster's recent league game against Cardiff Blues but he withdrew to fly to Australia on compassionate grounds.
With 11 members of Tony McGahan's current squad departing, the obvious question is who will replace them and as is their wont Munster will primarily look to within.
It has been well-documented that former Ireland Under-20 full-back Felix Jones is on his way south from Dublin but he is the only 'outsider' at this stage.
Back rower Billy Holland and centre Tom Gleeson will move from development to full contracts and Academy players Tommy O'Donnell, another back rower, and Dave Ryan, a prop and younger brother of Timmy Ryan, will move up to development contracts.
In further news, Ciaran O'Boyle is back training having recovered from the injury sustained in his try-scoring appearance against the Dragons in March, while Darragh Hurley is also on the mend following minor neck surgery last month.
Former Garryowen hooker Damian Varley, after a full season in the professional set-up with London Wasps, returns to take up a contract with Munster.
All those, plus the players not on Ireland or Lions duty, will report back for pre-season training on June 29.