Glycosaminoglycans were isolated from the four sections (tip, upper, middle and base) of the main beam of growing antlers of wapiti (Cervus elaphus) by papain digestion and DEAE-Sephacel chromatography. Chondroitin sulfate was the major glycosaminoglycan in each section of antler accounting for, on average, 88% of the total uronic acid. The yield of chondroitin sulfate liberated from the tissue was approximately 6-fold greater in the cartilaginous (tip and upper) sections than in the bony (middle and base) sections. This was consistent with the higher intensity of glycosaminoglycan staining with either Alcian Blue or Safranin-O. The majority (average 88%) of chondroitin sulfate was precipitated with 40 and 50% ethanol. The average molecular size of chondroitin sulfate determined by gel chromatography on Sephacryl S-300 tended to be greater in the 40% ethanol than in the 50% ethanol fraction. In either fraction, the molecular size of chondroitin sulfate was smaller in cartilaginous tissues than in osseous tissues of growing antler. In addition to chondroitin sulfate, the antler contained small amounts of hyaluronic acid, dermatan sulfate and keratan sulfate. The immunohistochemical study showed wide distribution of chondroitin sulfate, decorin, and keratan sulfate throughout the antler. On the other hand, keratan sulfate was more prominent in the cartilaginous sections than in the bony sections where the anti-keratan sulfate monoclonal antibody staining was seen in the osteoid tissue only.