Stages of oocyte maturation in sea bass (Dicentrarchus labrax) gonads after LHRHa hormonal treatment were investigated. LHRHa was injected into sea bass broodstock with an oocyte diameter of 527-580 mu m. A second injection was given 12 h after the first injection. For each injection a dose of 10 mu g/kg was used. At 24 h, oil globules in oocytes were randomly distributed. These oil globules started to fuse and change to a spherical shape from an ellipsoidal shape at 36 and 42 h. Ovulation was observed between 45 and 54 h after the first intramuscular injection. After 54 h from the first injection, oocytes became overripe due to no spawning occurring on time. The overripe rate in gonads was 90% at 60 h.