Cultivation of summer rice in the flood-prone areas of Assam has gained momentum through massive public investment on STW, especially in the non-traditional areas. The crop has shown high productivity in the medium land at higher level of technology, which needs repeated application every year. The process has paused threat to the marginal and small farmers who are resource-poor. The study has analysed the growth and stability of summer rice and economics of its cultivation in the flood-prone districts of Assam. It has been observed that summer rice has grown faster than autumn and winter rice during the past four decades. Irrigated HYV summer rice in the medium land is costly to cultivate but is more productive at higher level of technology. Yield advantage of summer rice has been found to be higher than that of autumn and winter rice. High cost and low product price, land degradation due to over-use of chemical fertilizer, high cost of irrigation, prevailing market distortion, and lack of short-duration photoinsensitive varieties have been identified as main constraints for summer rice cultivation in the non-traditional areas. Absence of strong linkage between commodity and money market has been found in the rice producing areas for marginal and small farms.