Rehabilitation didn't get much attention in animal research as compared to disuse atrophy that has been widely investigated over the years. We therefore performed a combined morphometrical and biochemical study on the effect of recovery from hind-limb immobilization on the tibia and the serum of rats. The experiments were carried out on 42 young Sprague-Dawley male rats. In one group of 32 rats the left hind-limb was immobilized for 2 weeks and then remobilized for another 2 weeks. Another group of 10 rats served as controls. Total body weight was partially restored. Tibia weight (fresh, dry and ash) showed on the other hand no tendency to improve. Serum triglycerides, urea, creatinine, albumin and calcium that were found to be reduced during immobilization returned to normal values during the rehabilitation period. Serum phosphorus that remained normal during limb disuse rose to above normal values in the remobilization phase. Serum alanine aminotransferase levels changed from low to normal. Serum alkaline phosphatase showed a rebound phenomenon from low to above-normal. Both muscle aspartate aminotransferase and bone alkaline phosphatase that were low during immobilization returned to normal in response to rehabilitation. We conclude that biochemical alterations are fast and tend to become fully corrected. Overcoming weight loss is a much slower process and it is unclear whether weight ever returns to pre-atrophic values.