On-farm farmers’ participatory trials were carried out in five different villages of Tangi Block in the Khurda district of Orissa during the crop growing season of 2001-02 and 2002-03 to study the effect of duration of different rice varieties on the performance of succeeding blackgram crop in rice–blackgram utera cropping system under rainfed shallow lowland. The highest grain yield of 5.7 t ha^-1 was recorded with the improved high yielding variety of rice cv. Moti (155 days). While, the highest seed yield of blackgram (0.68 t ha^-1) was achieved in the treatment plots where the improved rice variety Swarna (135 days) was raised during the wet season. The highest net return (Rs. 23163 ha^-1) as well as benefit : cost ratio of 3.07 was recorded in the treatment where rice variety, Moti was adopted in rice – blackgram utera cropping system.