Raw, sucrose solution cooked and boiled mung beans were evaluated for protein quality in vivo using rats and for trypsin inhibitor activity in. vitro. Heat treatment did not significantly improve the protein quality of mung bean at 2% and 8% level although the PER, RPV, NPU values and growth performance of rats fed boiled mung bean was higher than those fed raw mung bean. However,the PER and NPU values of 5% boiled mung bean differed significantly from raw mung bean and mung bean cooked with sucrose solution. Sugar medium decreased the nutritive value and proximate protein content lower than raw mung bean. The standard protein source, skim milk, was twice as better than any of the mung bean treatments.