The study used farm level data collected from rainfed and irrigated castor seed cultivators from three purposively selected districts namely Rewari, Sirsa and Hisar of Haryana on the basis of highest acreage under castor crop. From each selected district, two villages were selected purposively having large number of castor cultivators. Sixty castor cultivators were interacted to extract relevant information related to various resources utilized in castor seed production using survey method. The results of Cobb-Douglas production function indicated that difference between MVP of machine labour, seed, chemical fertilizers, irrigation and its unit price was found to positive and significant in Rewari district. Similarly in case of Sirsa district machine labour, seed, plant protection and irrigation and in Hisar district human labour, seed, chemical fertilizers and irrigation was found to positive and significant indicating that these inputs were underutilized. The elasticity of production was found to be positive in Sirsa and Hisar district while in Rewari district it was negative. It is concluded from the results that in Rewari district the excess use of resources should be curtailed for achieving the profit.