We report the contamination rate in the Cambridge bone bank of 35 consecutive allograft specimens, all harvested in a clean-air environment, using a strict aseptic technique and antibiotic cover. Five of 27 femoral heads taken from living donors and three of eight massive allografts taken from cadavers were found to be contaminated. The contaminated femoral heads were discarded. All massive allografts were rendered sterile by gamma-irradiation. It is important to exclude bacteriological contamination of harvested and banked bone.