Eighteen Ossimi rams of about 40.63 kg body weight were used to evaluate the impacts of betaine supplementation on carcass characteristics of Ossimi rams. Animals were assigned randomly to three treatment groups (CO, BET¹ and BET²), the control group was fed a BET free diet while BET¹ and BET² groups received 2.0 and 4.0g BET/h/d for 120 days experimental period. three rams from each group were slaughtered at the end of the experiment. The results revealed that, BET² group increased (P≤0.05) fasting and empty weight compared with BET¹ and control groups. Hot carcass and carcass weight without tail tended to be heavier in BET treated rams than control. Betaine supplementation led to improve the dressing percentage compared with control. Carcass measurements influenced significantly due to feeding  on betaine. A significant increase in weights of liver and sex organs of BET² than BET¹ and control diets. Fed betaine caused a significant (P≤0.05) lower in carcass fats than control. Testicular morphology increased (P≤0.05) in treated animals. BET² were higher (P≤0.05) leg weight and length than control. Weights of shoulder, fore shank and breast were heavier (P≤0.05) in BET² than BET¹ and control groups. Betaine supplementation increased (P≤0.05) weights of 9,10 and 11 ribs cut and muscle weight and lower (P≤0.05) fat and bone weight compared with control. All individual skeletal muscle measurements were higher in rams fed on BET than control. No significant differences among treatments on chemical composition of muscles. In conclusion, betaine supplementation may improve carcass characteristics of treated rams.