<p> We investigated the light and temperature dependence of photosynthesis and its seasonal variations in the loquat cultivar 'Mogi' grown in a pot in an orchard. Leaf photosynthesis was light saturated in each season. The optimum temperature, at which net photosynthetic rate (<i>Pn</i>) was maximal, varied seasonally: 15°C in the fall, 5°C in winter, 20°C in spring, 25°C in the rainy season, and 30°C in summer. Maximum <i>Pn</i> value was 11-12 μmol CO<sub>2</sub> m<sup>−2</sup> s<sup>−1</sup> in the fall and summer, 2 μmol CO<sub>2</sub> m<sup>−2</sup> s<sup>−1</sup> in winter, and 6-10 μmol CO<sub>2</sub> m<sup>−2</sup> s<sup>−1</sup> in spring and rainy season. Thus, our results suggested that loquat photosynthesis is temperature dependent. When loquat was moved to a phytotron in winter and kept at 13°C for 2 weeks, its maximum <i>Pn</i> increased considerably and almost reached the value of loquat that was continuously cultivated in the phytotron at 13°C during winter.</p>