Physicochemical changes in three different commercial yoghurt brands were studied during twelve days storage at 10o, 25o and 45oC. A significant decrease in pH and an increase in titratable acidity occurred at all storage temperatures. At 10oC, moisture, lactose, fat, casein nitrogen, non-casein nitrogen and nonprotein nitrogen remained unchanged. However, total nitrogen content remained constant. At 25o and 45oC, moisture, lactose, fat, casein nitrogen and non protein nitrogen decreased to various extents. Results of sensory evaluation showed that all yoghurt brands stored at 10oC were acceptable till the twelfth day. On the other hand, sensory quality characteristics were adversely affected at 25°C and 45°C, after twelve days.