Hand hygiene behaviour in 71 healthcare professionals was observed on hospital wards for a total of 132 h, encompassing 1284 hand hygiene opportunities. Questionnaires completed by the participants were used to compare actual behaviours with self-reported behaviours, as well as intentions and attitudes towards hand hygiene. Observed practice showed very poor rates of adherence to guidelines and indicated that staff failed to take account of risk, even with patients colonized with meticillin-resistant Staphylococcus aureus. Observed practice was unrelated to carers' intentions and self-reported behaviour. The results suggest that hand hygiene interventions that target changes in attitudes, intentions or self-reported practice are likely to fail in terms of changing behaviour, and consideration is given to how this could be remedied.