Celosia argentea LINN. commonly known as “Cocks Comb” and its seeds are widely used in Indian folk medicine for the treatment of diabetes mellitus. This study was undertaken to evaluate the effect of an alcoholic extract of Celosia argentea seeds (ACAS) on blood glucose and body weight in alloxan-induced diabetic rats. ACAS was found to reduce the increase of blood glucose in alloxan-induced diabetic rats (27.8% at 250 mg/kg and 38.8% at 500 mg/kg body weight). Chronic administration of ACAS significantly (p<0.01) reduced the blood glucose in alloxan-induced diabetic rats for two weeks. Also the extract prevented a decrease in body weight in alloxan-induced diabetic rats. These results suggest that the ACAS possesses anti-diabetic activity in alloxan-induced diabetic rats.