The effects of heat treatments, namely microwave, infrared, hot air oven, autoclaving and cooking in boiling water, on trypsin inhibitor and haemagglutinating activities, tannin and phytate contents, essential amino acid composition and quality of proteins in winged bean, were investigated. The infrared, autoclaving and boiling-water treatments destroyed most of the trypsin inhibitor and haemagglutinating activities, and reduced the level of tannins. However, the microwave and oven heat treatments had no effect on these constituents of winged bean meal. Lysine and valine contents in the meals from infrared, autoclaving and cooking in boiling water treatments were lower than in untreated meal. There was a significant loss of threonine and arginine due to cooking of beans in boiling water. None of the treatments had any effect on phytate content.