Impact of climate change on rice yield variabilities under various Representative Concentration Pathways (RCPs) has been estimated for Jorhat district, under Upper Brahmaputra Valley Agroclimatic Zone of Assam. CERES-Rice module of DSSAT 4.5 was calibrated and validated for rice cultivar ‘Mahsuri’ under three different dates of transplanting between May and July. Increase in both maximum and minimum temperatures at Jorhat, under all the RCPs for 2020, 2050 and 2080, suggests increasing level of heat stress during crop growth period. The deviations in projected grain yield over observed mean yield of 2009-2013 was found ranging from -12.7 to -43.4 per cent under all the scenario and dates of transplanting. Among all the climate scenarios, the reduction in grain yield was highest (-43.4%) under RCP 8.5 and lowest (-12.7%) under RCP 2.6.The mean yield reduction, considering all scenarios together, was highest in second transplanting date(-38.5%), followed by third(-28.8%) and first one (-23.3%).