This long-term retrospective study investigated the value of debridement versus debridement and Osteoset T antibiotic-loaded calcium sulphate pellets in the treatment of adult chronic osteomyelitis. Sixty-five patients were included in the study. The mean follow-up was 75 months (range: 36 to 334). Forty cases were treated by debridement, and 25 by debridement and Osteoset T. The healing rates were 60% and 80%, respectively; however, the difference was not significant. In a subgroup of 39 patients with medullary osteomyelitis and a normal immune system (IA according to the Cierny-Mader classification of adult osteomyelitis), 22 patients were treated with debridement, 17 with debridement and Osteoset T. The healing rates were 59% and 94%, respectively (p < 0.05). Twenty-eight patients with Staphylococcus aureus osteomyelitis were also studied apart; 13 were treated with debridement and 15 with debridement and Osteoset T. The healing rates were 46% and 80%, respectively. The difference was not significant. The results obtained with debridement were less good than with debridement plus Osteoset T, but the difference was not significant, except in a single subgroup. Osteoset T obviates the need for removal, which is the rule after implantation of gentamycin beads. Bony ingrowth is however limited.