Martin Valko
- Born
- 13 April 1971 (55 years)
- Place of birth
- Czechoslovakia
- Gender
- Male
Martin Valko, also known as Sergej Petronov, is a former Slovak pornographic actor who appeared in gay porn movies and magazines. He is 6'1", and weighed about 190 lbs. when he was making movies. He performed in both the top and bottom roles. Valko was in a car accident in 1997 that ended his video career and injured him badly, although he did recover.
