The antidiabetic activity of Momordica charantia (bitter gourd) fruit Methanol Extract (MCE) was investigated in normal and diabetic rats. Animals were treated intraperitoneally with a single dose of 120 mg kg-1 alloxan to induce diabetes. This resulted in significant increase in plasma glucose level. The diabetic and normal rats were both randomly divided into 5 groups. Group A (control) received distilled water ad libitum. Groups B, C and D were treated orally with daily doses of 200, 400 and 600 mg kg-1 of MCE respectively for 28 days. Group E received 10 mg kg-1 chlorpropamide for the same period. Administration of MCE produced a dose-dependent decrease in blood glucose level in both normal and diabetic animals. The decrease was significant (p<0.05) with 400 and 600 mg kg-1 of the extract. This is comparable to the effect of clorpropamide. Contrary to some negative findings, the results of this study show that chronic oral administration of extract of Momordica charantia fruits at an appropriate dosage may be a good alternative antidiabetic agent.