This study was conducted to determine the effects of 28-homobrassinolide (Hbl) applied postharvest on the storage quality of medlar fruit (Mespilus germanicaL.). Fruits were submerged into the solutions containing 3 and 5 mu M Hbl for 5min. Control fruits were submerged into distilled water for the same duration. Treated and control fruits were stored at 0 degrees C and 95% relative humidity conditions for 60days. Samples were taken at 15, 30, 45 and 60th day of storage. On the sampling dates, soluble solid content (SSC), pH, titratable acidity (TA) in malic acid, fruit firmness, weight loss, taste, browning, and color of the skin and pulp were analyzed. Results showed that these properties of the fruits changed over time in the storage and depended on the concentration of the homobrassinolide. 3 mu M Hbl treated fruits kept their firmness and initial weight longer. Fruits with 5 mu M Hbl application resulted in high TA and low SSC and provided best browning in the fruit skin. Taste was better attained and protected over alonger time with 5 mu M Hbl treatment. In conclusion, 28-homobrassinolide exerted some effects on quality of medlar fruits.