Abstract A three-month prospective surveillance study was undertaken in four dialysis centres to establish the prevalence of Staphylococcus aureus carriage in a Danish population of patients on haemodialysis (HD) or on continuous ambulatory peritoneal dialysis (CAPD). General data such as sex, age, diagnosis, number of months in dialysis, hospital and ward were registered on a precoded form. Standardized nose and four skin swabs (axillae, groins, perineum) were performed on the first day of the survey. After one and two months, nose swabs were collected. Infections were registered and cultures were sent for phage-typing together with the S. aureus strains isolated from the swabs; 59·5% of HD patients and 51·2% of CAPD patients carried S. aureus. Permanent carriage was most frequent ( P < 0·00009), primarily in the nose (44·0 and 34·9%, respectively in HD and CAPD). Skin carriage alone was rare (2·4 and 4·7%). Approximately one third (36·6 and 40·7%) of infections were caused by S. aureus. Although diabetics were not significantly more frequent carriers (60·5%) than non-diabetics (55·0%), the incidence of infection was much higher (26·3% vs. 10·3%, P = 0·004). In CAPD, peritonitis and tunnel/exit-site infections pre-dominated (81·4%), often caused by S. aureus (34·8%). More than two thirds of the infections in HD patients were related to intravascular catheterization. The most serious infection was septicaemia, in all cases due to S. aureus. S. aureus infections occurred significantly more frequently among carriers ( P = 0·005), and more than half the patients were infected by the same or possibly the same strain as they carried in the nose or on skin. Different regimens for the elimination of S. aureus carriage in dialysis patients are discussed. A policy for risk assessment of patients should be developed, and the elimination of S. aureus carriage before dialysis should be encouraged. Controlled trials comparing the cost-effectiveness of recommended regimens to eliminate carriage in HD/CAPD patients are needed. Nose swabs are reliable indicators of carriage in dialysis patients.