The former lawmaker said that he had not received any unlawful requests from Raimondas Kurlianskis, a former vice-president of MG Baltic, one of Lithuania's biggest business groups.
"I do not admit to being guilty," he told the Vilnius Regional Court.
Prosecutor say that Kurlianskis gave 106,000 euros to Masiulis as a bribe for pushing through decisions favorable to the business group.
Both defendants insist that the 90,000 euros in cash found at Masiulis' home was a loan from Kurlianskis.
"As a politician, I had to communicate with different groups. That was why I communicated with Kurlianskis as well. He did not make any unlawful requests," the former lawmaker told the court.
Masiulis dismissed charges related to his participation in a television program as a violation of freedom of speech.
"I'm accused of participating in a TV program. I am the first to stand trial for participating in a TV program. I am being persecuted for freedom of speech. I am convinced that this accusation is anti-constitutional", he said.
The prosecution claims that Kurlianskis arranged for Masiulis to appear on programs of TV channels owned by MG Baltic.