Martinez - a record 40 million euro signing from Athletic Bilbao this summer - tried on the traditional Bavarian outfit a day after helping Bayern complete a 3-1 win over Mainz.
He came off the bench to supply Toni Kroos with the third goal in stoppage time, and Martinez said about the lederhosen: "Very good, I have to say. Obviously it was all new to me, I've never worn anything like it before. But it's very comfortable indeed."
Bayern turn their focus to a Champions League match with Valencia on Sunday, and Martinez said: "I've never played in the Champions League before. It's an important match for us. Bayern made it to the final last season, and we're among the favourites for the competition, so we obviously want to make a successful start.
"I know their team (Valencia) very well and I've played them quite a few times. They'll definitely push us hard because they have a great team."
- Toni Kroos