Objectives: This study examined individual and combined effects of the cancer treatments goserelin acetate (GA) and doxorubicin (DOX) on bone and determined if treadmill running (TM) provides osteoprotection. Methods: Ten-week-old female Sprague-Dawley rats were randomly assigned to sedentary (SED) or TM groups. SED received GA, DOX, combined GA and DOX (GA+DOX), or placebo and maintained normal cage activity. TM received GA, DOX, GA+DOX, or placebo and participated in a progressive motorized treadmill protocol. After 8 weeks, tibiae were evaluated using micro computed tomography. Results: Negative drug effects were observed in cancellous bone (bone volume/tissue volume, trabecular number, trabecular thickness, trabecular spacing; P<0.05). An additive bone volume/tissue volume and trabecular spacing effect was observed in SED GA+DOX (vs. SED+GA and SED+DOX, P<0.05) but not in TM GA+DOX (vs. TM+GA and TM+DOX, P>0.05). Negative drug effects were observed in cortical bone (cross-sectional volume, cortical volume, marrow volume; P<0.05), but combined GA+DOX did not exacerbate these effects. Additionally, there were no protective cortical bone effects observed in TM. Conclusions: Combined GA+DOX exacerbates cancellous osteopenia in the tibia, and treadmill running provided only minor protection.