Nosocomial infections are an important cause of morbidity and contaminated equipment may contribute to this. There has been little work concerning contamination of non-disposable equipment in Otolaryngology. This study investigates the efficacy of the cleaning regimen for non-disposable instruments in an Otolaryngology out-patients clinic. Instruments were swabbed before each clinic, when they had been autoclaved, then after use on patients, when they had been washed with detergent and chlorhexidine. Swabs of 86 instruments were cultured using standardized microbiological techniques. Fifteen instruments (17 per cent) were contaminated, most with coagulase negative staphylococci. Two specimens of Micrococcus luteus were cultured and one each of Pseudomonas aeruginosa, Acinetobacter lwoffii and Aureobacterium spp. Micrococcus luteus and coagulase negative staphylococci may represent skin contaminants, but Aureobacterium spp. and Acinetobacter lwoffii can be sources of nosocomial infection. Pseudomonas aeruginosa is a potentially serious pathogen and is implicated in the aetiology of otitis externa. These findings question the efficacy of the current cleaning techniques.