Increasing air temperature (T) negates the positive effects of increasing atmospheric CO₂ concentration ([CO₂]) on rice in the tropics. We studied the impact of both increased T and [CO₂] on spikelet sterility and grain yield of different medium duration varieties of indica rice (Oryza sativa L) under lowland field conditions using open top chambers. Rice varieties were exposed to high (570 µmol mol^-1) or ambient [CO₂] and ambient or ambient + 3 ℃ air temperature throughout the growth period. Different varieties responded differently to increased [CO₂] and temperature. With increased atmospheric [CO₂], grain yield of different varieties increased by 6.6% to 43.8%. Increasing T decreased grain yield by an average of 23.7%, which also varied between varieties. Pollen fertility decreased with increased T. The reduction of pollen fertility was relatively low which could be due to decreased relative humidity at flowering. The negative impact of high temperature on pollen fertility, grain yield and yield components decreased significantly with the increase in atmospheric [CO₂]. Increased [CO₂] decreased transpiration while it increased with an increase in T. Increased pollen sterility with increased atmospheric T was due to increased spikelet temperature.