AbstractRats were exposed to a 60‐Hz electric field at an unperturbed field strength of 100 kV/m to determine its affect on bone growth and fracture repair. Exposure of immature male and female rats for 20 h/day for 30 days did not alter growth rate, cortical bone area, or medullary cavity area of the tibia. In another experiment, midfibular osteotomies were performed and the juvenile rats were exposed at 100 kV/m for 14 days. Evaluation by resistance to deformation and breaking strength indicated that fracture repair was not as advanced in the exposed animals as in the shamexposed animals. In another experiment measurements of resistance to deformation were made in adult rats at 16, 20, and 26 days after osteotmy. Fracture repair was slower in exposed compared to control animals at day 20 and, to a lesser extent, at day 16, but not at day 2