Sustanon is a well-known anabolic drug that is used to treat hypogonadism and restore muscle mass and bone density. As research to date has been limited to its effects in glycolytic fibers, this study aimed to investigate the dose-related effects of Sustanon on the oxidative fibers of avian skeletal muscle. Adult female chickens were randomly divided into 4 groups: control (C), received a dose of 100 μl normal saline per injection; and Sustanon-1, -2, and -3 (S1, S2, and S3), that received a dose of 12.5, 25, or 50 mg/kg Sustanon per injection, respectively. Each bird received 4 injections at weekly intervals (1 injection/week). Robust histochemical and immunofluorescent techniques along with morphometric analyses were applied to determine the oxidative activity and morphological variations of the oxidative muscle fibers in all groups. Sustanon-treated groups exhibited significant increases in fiber size and numbers of satellite cells and myonuclei compared to the control group. However, no significant variations were found between Sustanon-treated groups in the aforementioned indices. In conclusion, Sustanon induced oxidative fiber hypertrophy that was associated with satellite cell proliferation and myonuclear accretion in avian skeletal muscle. Furthermore, the effects of Sustanon appeared to be dose-independent.