The temperature responses of photosynthesis of two rubber clones, RRIM600 and PB260 were determined over a wide range from 10 to 45°C. Leaf photosynthesis measurements were performed at the Agriculture Faculty, Kasetsart University, Thailand and in a growth chamber at French National Institute for Agricultural Research (INRA-PIAF), Clermont-Ferrand, France. Photosynthetic rate of RRIM600 stayed almost constant between 23 to 37°C, and decreased distinctly with increasing temperature from 38 to 45°C. Photosynthetic rate of PB260 increased with increasing temperature from 10°C, and also decreased distinctly by lowering the temperature below 24°C or by increasing it above 36°C. These results indicated the similar shape of temperature response of photosynthesis of two rubber clones.