The reproductive biology of the Mediterranean snake eel, Ophichthus rufus (Ophichthidae), was studied on the basis of microscopic and macroscopic analysis. Results show that O. rufus is an ovuliparous species with a group synchronous ovary type. The maturation process of the gonads starts in December and progress untill August, when ovulation and spawning take place. It is a fractional spawner with buoyant eggs. Potential annual fecundity estimates ranged from 1426 to 23,605 oocytes. Except for small sizes, a clear predominance of females was observed.