The field experiment was conducted during kharif seasons of 1994 and 1995 to study the efficacy of bio-fertilizer on finger millet (Eleusine coracana L. Gaertn.) under lateritic acid soil (pH 5.8) of Sekhampur, Birbhum in West Bengal under rainfed condition. Raising the level of nitrogen from 0 to 80 kg/ha increased the growth, yield attributes, yield and NPK uptake by the crop. Higher of nitrogen 80 kg/ha produced significantly and economically higher yield under rainfed red leteritic soil. Seed inoculation of Azospirilium gave an additive effect over FYM, nitrogen and phosphorus application alone and the effect of Azospirilium was found to be equivalent to 20 kg N/ha through urea. The combined application of Azospirillum and nitrogen gave better effect that Azospirillumwith phosphorus. However, rock phosphate recorded at par effect on growth and yield with SSP. Highest dry matter (409.8 g/m2), LAI (1.15), ear heads/m2 (120.5), length of finger (7.2 cm), NPK uptake (126.2 kg/ha) and grain straw yield (1320.7 and 2771.3 kg/ha) were obtained by Azospirillum + Nso followed by N80 and Azospirillum + N60 which also gave at par effect. Sole application of Azospirillum recorded 51.12% higher grain yield than control.