Adult male rats maintained on a low calcium intake during 6 weeks prefracture developed osteoporotic changes of the tibia fracture during a healing period of another 6 weeks.Treatment based on combined use of daily peroral doses of 1α-hydroxycholecalciferol and an optimal calcium intake reversed the osteoporotic changes in the fractured tibia after only 2 weeks, and the act of reversion became still more pronounced after 4–6 weeks.1α-hydroxycholecalciferol treatment is recorded, when supported by an optimal calcium intake, to positively influence the levels of serum calcium, dry weight, and total ash content as specific weight and cortical thickness of the fractured tibia, following experimental fractures.