The 33-year-old former France defender, who was passed fit to return to training with his team mates last month, is a huge favourite with the Barca fans and was greeted with a rousing ovation when he replaced Gerard Pique in the 70th minute.
In a pitch-side television interview with Spanish broadcaster Canal Plus, Abidal thanked the cousin who provided part of his liver for the procedure.
"It was a very special moment for me after a year out," said Abidal, wearing a shirt with 'Merci mon cousin' on the front.
"I want to thank my cousin as without him I would not be here today. It is a unique moment," he added.
Abidal's return is well timed as Barca centre backs Carles Puyol and Javier Mascherano and full back Adriano are all out injured at a critical stage of the season.
Barca, 13 points clear of Real Madrid at the top of La Liga, play the second leg of their Champions League quarter-final against Paris St Germain at the Nou Camp on Wednesday after last week's first leg ended 2-2.
- Sports & Recreation
- Gerard Pique