Moringa oleifera seeds are used as dietary supplement in developing countries. Phytochemical, proximate constituent and acute toxicity test were determined. Aims of the study were to investigate the effects of Moringa oleifera aqueous seed extract on live body weight and scrotal circumference of Yankasa rams. 25 apparently healthy Yankasa rams aged 1-2 years weighing (18-20 kg) were purchased and kept at the experimental pen of the Department of Veterinary Parasitology and Entomology, ABU, Zaria. Rams were acclimatised and screened for endo and ecto-parasites prior to commencement of the experiment. Rams were randomly divided into five groups (A, B, C, D and E; n = 5) treatment groups and control group, respectively. The rams were fed basal diet of Digitaria smuttssi and supplemented with bean husks and maize offal. Water and salt lick were provided ad libitum. Groups A, B, C and D were given oral dose of Moringa oleifera aqueous seed extract at a dose rate of 1000, 2000, 3000 and 4000 mg/kg, respectively, while group E (control) received water (10 mL/kg), daily, for five months between 7:00 AM and 9:00 AM. Results of live-body weight showed significant (P < 0.05) monthly (April-June) increase in rams treated with different doses of M. oleifera aqueous seed extract compared to their respective initial weight in (March), with the highest and lowest in group D and A (26.671±0.3) and (24.89± 0.5) respectively, compared to the control group E (24.63±0.4). There was significant increase in scrotal circumference of Yankasa rams administered with different dose of Moringa oleifera aqueous seed extract compared to the control group. Inclusion, Moringa oleifera aqueous seed extract could be used to increase live-body weight and scrotal circumference of Yankasa rams.