1. As previous experiments with autogenous transplantation of epiphysial growth plates have given limited success, a study was carried out on two groups of rabbits, one of which was given hyperbaric oxygen post-operatively in an attempt to improve the results.

2. Sixty-four New Zealand white rabbits had the distal ulnar growth plate transplanted from left to right and vice versa, giving a total of 128 transplants.

3. In the group of thirty-two rabbits given hyperbaric oxygen 48 per cent of the transplants were regarded as successful when examined histologically six weeks after operation, while in the control group the figure was 28 per cent.

4. This investigation suggests the clinical use of hyperbaric oxygen to improve the results of transplantation of growth cartilage.