In this study, the effects of administration of commercial probiotic, Bacillus sp., were examined on growth parameters and digestive proteases (alkaline and acid proteases) activities in gilthead sea bream, Sparus aurata, during larval development until on day 40. Probiotics were supplemented in triplicate from on day 3 coinciding with starting of exogenous feeding. In the experimental group, probiotic was introduced to rotifer and tank water until 20 days after hatching. Also, control group did not receive probiotic. In experimental group, the specific activities of alkaline protease was significantly higher (p<0.05) in larvae compared to control group. Acid protease activity was not effected by probiotic supplementation however, it was relatively higher in experimental group than the control (p>0.05). Additionally, no significant differences were found in both survival (8.5% higher) and specific growth rate (0.7% higher) larvae of S. aurata that had probiotic supplemented by rotifer with water as compared to controls (p>0.05). Consequently, specific activities of alkaline and acid protease could be significantly increased by the administration of Bacillus sp. to live food with water the and therefore; this method would be more effective for obtaining of relatively better growth parameters and nutritional condition in S. aurata larvae.