Trypsin inhibitor and hemagglutinating activities of some minor beans produced in Korea were determined in comparison with those of soybean and the effects of heat treatment on the activities were studied. The results are summarized as follows 1. The trypsin inhibitor activity (% [TU] inhibited/mg) of soybean, red bean, kidney bean, and mung bean were 79.9, 46.4, 43.2 and 17.7, respectively, on the dry weight basis and were 194, 222, 170 and 75, respectively, on the protein basis. 2. Heat destruction by boiling or autoclaving of trypsin inhibitor activity of red bean, mung bean, kidney bean, and soybean were $85{\sim}87,\;87{\sim}94,\;76{\sim}79\;and\;67{\sim}72\;%$, respectively. No significant difference was, however, observed in the effect between the two heating methods. 3. The hemagglutinating activity (unit/g) of kidney bean, soybean, mung bean and red bean were 48,300, 18,000, 136 and non-detectable, respectively, on the dry weight basis and were 190,600, 43,700, 581 and non-detectable, respectively, on the protein basis. Heat treatment destructed the hemagglutinating activity in all three beans.