Intercropping castor (paired row planting at 60/120 cm x 60 cm) with three row of green gram was found highly cost effective under irrigated ecosystem. This system yielded higher castor equivalent yield (55.34 q ha-1), net returns (Rs 57334 ha-1) and B: C (4.95) without affecting nutrient status of the soil. Further, when cultivation of castor is intended as sole crop, uniform row planting at 90 cm x 60 cm may be preferred. Thus, these findings may be recommended to the farmers of zone IVa of Rajasthan (Sub-humid southern plain and Aravalli Hills) for breakthrough in castor cultivation.