Dental hospital staff and students were observed during clinical work for their compliance with infection control procedures, as recommended by the British Dental Association. A total of 183 contacts between health care worker and patient were scrutinised during December 1990. Nearly all health care workers (96%) wore gloves to carry out dental treatment, but in some cases gloves were neither changed nor hands washed between patients. Only one half wore protective eyewear and about one third (38%) wore no mask. Some dental surgery assistants used heavy duty gloves and some even scrubbed dirty dental instruments without wearing any gloves. Strict audit is clearly needed in every clinical setting in order to ensure compliance with infection control.