The possibility of crop diversification in existing rice-wheat system was explored under irrigated eco-system of Varanasi. The treatments comprising ten crop sequences viz. rice-wheat, rice-chickpea, rice-wheat-green gram, rice-wheat-Sesbania (green manure), rice-mustard-green gram, rice-lentil-cowpea (fodder), rice-pea (grain), rice-lentil + mustard (3:1)-cowpea (fodder), rice-maize (green cob) + vegetable pea (1:1) - cowpea (fodder) and rice-potato-green gram were arranged in a randomized block design under four replications. Results show rice-potato-green gram sequence gave highest rice grain equivalent yield (21.66 t ha^-1), net return (Rs. 64,192 ha-1), output input ratio (2.17), production efficiency (Rs 219 ha^-1 day^-1) and employed maximum labourers (421 ha^-1 year^-1) followed by rice-mustard green gram, and rice-maize + pea-green gram sequences. However, rice-chickpea sequence proved least remunerative. In general, land use efficiency, production efficiency as well as labour engagement were improved by inclusion of summer crops in sequence. Maximum amount of energy (173540 MJ ha^-1) was obtained from rice potato-green gram, followed by ricemaize (green cob) + vegetable pea (1:1)-cowpea (fodder) and rice-lentil + mustard (3:1)-cowpea (fodder) sequences. The net energy return and energy use efficiency were significantly higher in rice-potato-green gram sequence than in other sequences.