Osteoporosis is determined by decreased bone strength that increases the threat of fractures. The aim of this study was to evaluate the effects of pentoxifylline (PTX) and alendronate (ALN), on the stereological parameters, and gene expression in callus of fracture in an experimental rat model of ovariectomy-induced osteoporosis (OVX). The OVX was induced in 90 female rats. Fourteen weeks later, a complete fracture on the right femur was made. Rats were divided into five groups: 1) control: no treatment; 2) sham: received daily distilled water; 3) daily 3.00 mg kg-1 ALN subcutaneously (SC); 4) daily 200 mg kg-1 PTX (SC) and 5) daily PTX (SC) + ALN (same doses). The osteoclast count was significantly lower in all treatment groups, at 21 and 56 days post-surgery, compared to the control and sham groups. The PTX significantly increased total callus volume at 21 and 56 days post-surgery, compared to the other groups. The PTX+ALN treatment significantly increased both cortical bone volume on day 21, and osteocyte and osteoblast numbers on day 56, compared to the control and sham groups. It can be concluded that PTX and ALN have antiresorptive effects, in OVX rats. Also, PTX has increased the extracellular matrix on both 21 and 56 days after surgery, compared to the other groups. PTX+ALN elevated cortical bone volume on day 21, and osteocyte and osteoblast numbers compared to the control and sham groups on day 56.