Massive bone allografts sterilised by radiation have been used in our hospital since 1985. The 164 consecutive reconstructions which we carried out before December 1990 were in equal part for tumour resections and revision arthroplasties associated with major bone defects. The allografts were used as intercalary or composite graft-prosthesis reconstructions. Fourteen (8.5%) skin sloughs or infections occurred, all but one after operations for malignant tumours. The grafts never appeared to be responsible. Infection after malignant tumour resection most commonly occurred at the knee when preoperative radiation had been used. Twenty-five reconstructions were performed in the presence of infection, which only recurred in one case. Twelve infections were treated, but 2 other patients died for other reasons within a year. One patient had to have an amputation and one had persistent infection. In the other cases, the infection healed. Only two debridements alone were successful. Removal of the graft and replacement with antibiotic-loaded cement was the most effective treatment.