The separate and combined effects of intermittent parathyroid hormone (iPTH) (1–34) and mechanical loading were assessed at trabecular and cortical sites of mouse long bones. Female C57BL/6 mice from 13 to 19 weeks of age were given daily injections of vehicle or PTH (1–34) at low (20 μg/kg/day), medium (40 μg/kg/day) or high (80 μg/kg/day) dose. For three alternate days per week during the last two weeks of this treatment, the tibiae and ulnae on one side were subjected to a single period of non-invasive, dynamic axial loading (40 cycles at 10 Hz with 10-second intervals between each cycle). Two levels of peak load were used;​ one sufficient to engender an osteogenic response, and the other insufficient to do so. The whole tibiae and ulnae were analyzed post-mortem by micro-computed tomography with a resolution of 5 μm. Treatment with iPTH (1–34) modified bone structure in a dose- and time-dependent manner, which was particularly evident in the trabecular region of the proximal tibia. In the tibia, loading at a level sufficient by itself to stimulate osteogenesis produced an osteogenic response in the low-dose iPTH (1–34)-treated trabecular bone and in the proximal and middle cortical bone treated with all doses of iPTH (1–34). In the ulna, loading at a level that did not by itself stimulate osteogenesis was osteogenic at the distal site when combined with high-dose iPTH (1–34). At both levels of loading, there were synergistic effects in cortical bone volume of the proximal tibia and distal ulna between loading and high-dose iPTH (1–34). Images of fluorescently labelled bones confirmed that such synergism resulted from increases in both endosteal and periosteal bone formation. No woven bone was induced by iPTH (1–34) or either level of loading alone, whereas the combination of iPTH (1–34) and the “sufficient” level of loading stimulated woven bone formation on endosteal and periosteal surfaces of the proximal cortex in the tibiae. Together, these data suggest that in female C57BL/6 mice, under some but not all circumstances, mechanical loading exerts an osteogenic response with iPTH (1–34) in trabecular and cortical bone.