Background: Male infertility is considered a major cause of couple infertility as it represents 25- 50 % of infertility cases. In addition, non-obstructive azoospermia (NOA) represents 10% of all infertile men.There is no definite curable treatment for such cases. Aim of Work: The purpose of this research was to assess the efficacy of BM-MSCs and AT-MSCs in treating busulfan-induced azoospermia in wistar rats. Materials and Methods: BM-MSCs were extracted from the femur bones of five adult Wistar rats and AT-MSCs from preperitoneal adipose tissue. They were then evaluated for morphology, MSC markers, osteogenic and adipogenic differentiation. To produce azoospermia in male Wistar rats, two doses of busulfan (15 mg/kg and 30 mg/kg) were administered intraperitoneally during a 21-day period. The seminiferous tubules of each testis were injected with 2.5106 MSCs 35 days after the second busulfan injection. 12 weeks after cell therapy, the testes were examined histopathologically and histomorphometrically. Results: Like the control group, the seminiferous tubules treated with BM-MSCs demonstrated normal spermatogenesis in compared to the busulfan-induced azoospermic testes. In contrast to the busulfan-induced azoospermic testes, the seminiferous tubules treated with AT-MSCs exhibited