The present study was performed to investigate the aptitude of Lactobacillus acidophilus 04 isolated from home made curd as a probiotic in treating the vibriosis of freshwater river prawn (Macrobrachium rosenbergii). Both in vivo and in vitro analyses were performed to test their efficacy. The antagonistic effect of cell free extract obtained from L. acidophilus 04 biomass was tested against three pathogenic Vibrio spp. namely Vibrio harveyi, V. vulnificus and V. anguillarum using disk diffusion method. The result showed inhibitory effects of cell-free extract on all three Vibrio spp. A feeding experiment was conducted for a period of 30 days by incorporating L. acidophilus in shrimp feed in three experimental (T1,T2, T3) and one control groups. The result showed an increased gain in size and weight in experimental groups treated with L. acidophilus 04 compared to control group without any L. acidophilus 04 addition. The treatment groups were further challenged in vivo by inoculating shrimps with 104-106 cells of pathogenic Vibrio harveyi, V. vulnificus and V. anguillarum. The histopatholgical and microbiological analysis revealed significant variation (P <0.05) in morbidity and mortality rates between the three treatment (T1, T2, T3) and one control (C) groups. The result of the study indicates an obvious improvement in growth and survival rate of juvenile freshwater prawns injected with pathogenic Vibrio spp. upon feeding with L. acidophilus supplement.