The regeneration of the injured articular cartilage has been controversial subject among many authors. However, there is not detailed report pertaining to the effect of hydrocortisone on the repair of injured articular cartilage. The author, therefore, has undertaken an experimental study in order to observe effect of hydrocortisone on the repair of intra-articular cartilage in young growing rabbits. Forty rabbits weighting 1000 to 1500 gm were selected and the articular cartilage including at the distal end of femur in the knee was sosteotomised about 1.5X1.5 cm extending 5.0mm depth through the subchondral bone layer and replaced immediately into the original site, then each rabbit of experimental group was injected 1 mg hydrocortisone into the knee joint. After entire procedure, 5 animals from each group were sacrificed at 1st, 2nd, 4th and 8th week and the gross and microscopic examination of the specimen of transplanted articular cartilage was done through the longitudinal section. The result are obtained as following: 1. Articular surface revealed fragile fibrous tissue appearing later than control group. 2. Degenerative change was noted on the articular cartilage. 3. Necrosis and regeneration were delayed on both articular cartilage. 4. Bone regeneration in subchondral bone layer was inhibited. 5. Decreased fibroblastic proliferation was noted in subchondral bone layer. 6. Complete regeneration was noted at the postoperative 8 th week.