After an amateur career, he won the gold medal in European Amateur Boxing Championships in Belgrade, he turned professional in 1977, and won the European Boxing Union title in the light welterweight in 1979. Beneš retired from the ring in 1983, after a severe eye injury.
- Davor Pašalić (2 March 2004). "Boksački prvak koji se u svom kafiću tukao 15 puta dnevno" [A boxing champion who used to fight 15 times a day in his bar] (in Croatian). Nacional. Archived from the original on 30 June 2012. Retrieved 9 December 2015.
- "U Banjoj Luci umro legendarni boksač Marijan Beneš (67)" (in Croatian). 24 Sata. 4 September 2018. Retrieved 4 September 2018.