INTRODUCTION: Several pharmacological agents have been investigated for their ability to reduce orthodontic relapse. OBJECTIVE: The current research was performed to test the short term influence of systemic Co-enzyme Q10 administration on post-orthodontic relapse in rabbits. MATERIALS AND METHODS : Thirty New Zealand rabbits were randomly divided into 2 groups (n=15) : Experimental receiving Co-enzyme Q10 and control receiving control vehicle. Orthodontic tooth movement was performed using NiTi coil spring for 21 days for both groups, then this coil spring was detached, and teeth were allowed to relapse for another 21 days. Amounts and percentages of relapse were assessed on threedimensional models of the experimental and control groups at two time points (T2: 1 week of relapse) and (T3: three weeks of relapse). Animals were sacrificed after 3 weeks of relapse for histological examination using H&E stain. Also, histomorphometric analysis was performed. Statistical analysis was computed. Significance was judged at the 5% level. RESULTS: The amount and percentage of relapse showed insignificant difference among experimental and control groups, although relapse in the experimental group was less. However, the histological analysis showed that Co-enzyme Q10 resulted in significant reduction in osteoclast count with the area of new bone formation being significantly increased. Signs of bone resorption were more evident in the control group. CONCLUSION: From the present results, it could be concluded that Co-enzyme Q10 is capable of altering bone resorption pattern favorably in spite of its short term ineffectiveness in minimizing relapse.