This study was conducted to investigate the dietary effects of lactic acid bacteria (LAB) supplementation on growth, hematological and immune responses of grey mullet, Mugil cephalus. Three replicate groups of grey mullet (body length, $62.8{pm}1.04;mm$ ; body weight, $3.2{pm}0.13;mg$) were fed the experimental diets with 0 (control), 1, 2.5 and 5,0 % of LAB for 3 months. Total body length growth rate was increased in 2.5 % supplementation group compared to control (P<0.05). No differences were observed in hematological parameters (hematocrit, hemoglobin, RBCs) and serum chemistry (calcium, magnesium, total protein, glucose, GOT and GPT). The antioxidant activity of grey mullet fed the 5.0 % LAB diets was significantly higher than that of other groups (P<0.05). Both intracellular superoxide anion production and lysozyme activity of kidney were higher in the 2.5 % LAB diet than in the control (P<0.05).