Respiration and anaerobic glycolysis of fresh rabbit costal cartilage was compared with that of cartilage autografts and homo-grafts implanted from 7 to 150 days utilizing standard manometric methods. The mean QO2 for the fresh cartilage was -0.41 [plus or minus]0.04, while the [image] value was +0.70+0.08. During the first 7 days following transplantation approx. a 45% decline in respiration and anaerobic glycolysis occurred in both types of grafts. From 7 to 150 days there was no further significant variation. No salient difference between the metabolism of rabbit costal cartilage autografts and homografts was demonstrated.