The effect of light condition during post-harvest storage on fruit quality of 'Hakuho' peach (Prunus persica Batsch) was examined. Fruits were harvested at the immature stage (7 d before the tree-ripening stage) and firm-ripe (3 d before the tree-ripening) stage and stored at 25 degrees C under light (ca 80 micromol m(-2) s(-1) at the fruit top by a fluorescent lamp) and in darkness. The light and dark conditions did not significantly influence the ethylene production rate except for the fully ripened fruits harvested at firm-ripe stage and stored under light. However, no difference in fruit firmness was detected among treatments at full-ripe stage. The skin anthocyanin content increased significantly during storage under light. Total soluble solid (TSS) content of juice at the full ripe stage was not affected significantly by the storage condition, although titratable acidity (TA) in immature harvested fruits decreased more quickly during storage under light compared with those stored in darkness. Dark storage limited the decrease in juice asparagine to some extent. Aromatic lactones, such as gamma-decalactone and gamma-dodecalactone, both in skin and in flesh tissues increased more rapidly when the fruits were stored under a light condition, irrespective of fruit harvest stage. From these results, we conclude that fruit storage under a light condition is better for fruit quality of the 'Hakuho' peaches than storage in darkness.