An experiment was designed to evaluate the effect of dietary supplementation of Lactobacillus acidophilus on blood biochemical profile, antioxidant activity and plasma immunoglobulin level in neonatal Murrah buffalo calves. The 90 day trial was conducted on 24 neonatal Murrah buffalo calves randomly divided into 4 dietary treatments, viz. CON (basal diet alone), T1 (basal diet + L. acidophilus as a fermented milk @ 100 mL/calf/day having 108 CFU/mL), T2 (basal diet + L. acidophilus as a fermented milk @ 200 mL/calf/day having 108 CFU/ml) and T3 (basal diet + L. acidophilus as a fermented milk @ 300 ml/calf/day having 108 CFU/mL). Supplementation of probiotics improved the plasma glucose level in T2 and T3 as compared to CON. Total protein (TP), plasma albumin (A), plasma globulin (G) and A:G ratio did not change with the supplementation of probiotic in calves. Total cholesterol and HDL cholesterol levels in plasma remained same in all the 4 groups. Total antioxidant (TA) activity was higher in T2 and T3 as compared to CON, whereas it was intermediate in T1. Super oxide dismutase (SOD) activity was significantly higher in T1, T2 and T3 groups as compared to CON whereas catalase and glutathione peroxidase (GPx) activity remained same in all groups throughout experimental period. The total plasma immunoglobulin and plasma IgG remained uninfluenced in all the groups. In conclusion, supplementation of L. acidophilus improved energy metabolism and antioxidant capacity in neonatal Murrah buffalo calves.