This experiment was carried out using potted plants to assess the effect of keratin-based organic fertilizer produced from microbially hydrolysed feathers on cowpea’s. The fungus isolated and used for the hydrolysis of feather during the production of organic fertilizer was identified as Aspergillus niger. The results showed that the organic fertilizer was very effective on plants with soils amended with the hydrolysed feathers, as the plants exhibited better yields and productivity. Data for plant height (cm), weight of plant, number of leaves per plant and number of pods per plant were taken at weekly interval for a period of 9 weeks.. The various treatments used were 1kg/10kg of soil, 2kg/10kg of soil, 3kg/10kg of soil while 0kg/10kg served as control. Based on observation, the treated plants were less susceptibile to diseases compared to the non-treated plants. It was revealed that organic fertilizers application rate of 3kg/10kg had the highest performance in terms of growth and yield, and least susceptibility to diseases, the converse was observed for control. The result of this study was indicative that feather which is cheap, readily available and environmentally friendly offers a promising prospect in agriculture both as an organic fertilizer and in the control of disease in cowpea if applied at recommended rates and time.