Catheter exit site infection (ESI) remains a common complication in peritoneal dialysis patients. All the efforts for controlling ESI have been focused on the preventive eradication of Staphylococcus aureus (SA) colonization, because this microorganisms has been shown to be implicated in most of ESI. The main aims of the present study was to analyse the long-term results from an eradicative regimen of SA colonization, and to compare them with those obtained from a historical control group. From january 1993 to december 1999, 60 unselected patients on PD underwent an exhaustive protocol of SA eradication. Every 30-45 days, cultures from nares and exit site were obtained in each patient. SA colonization in nares or exit site was treated with mupirocin, though the colonization of other microorganisms was not treated prophylactically. Thirty patients from the same unit who were followed between 1989-1992 served as historical control group. The rate of peritonitis and ESI, as well as the epidemiological data from the cultures were also analysed. The peritonitis and ESI rates were significantly less in the study group than those in the control group (0.398 +/- 0.553 vs 0.899 +/- 0.970 ep./pat/year, p = 0.002; and 0.102 +/- 0.235 vs 0.340 +/- 0.553 ep./pat/year, p = 0.004). The ESI rate caused by SA was also significantly less in the study group (0.018 +/- 0.096 vs 0.300 +/- 0.53 ep./pat/year, p = 0.0001), though there was a statistically nonsignificant increase in the ESI rate caused by gram negative microorganisms in the study group (0.066 +/- 0.194 vs 0.040 +/- 0.219 ep./pat./year). The percent of patients free of ESI was larger in the study group (80% vs 63%, p = 0.01), though the percent of patients with more than one ESI was the same in both groups (10%). Nasal and exit-site SA colonization occurred in 52% and 32% of the study patients. The rate of catheter loss was less in the study group, though it did not reach statistical significance (0.043 +/- 0.154 vs 0.178 +/- 0.443 losses/pat./year). In conclusion, the eradication of SA colonization is an efficacious measure for the control of ESI. However, further efforts should be carried out in order to control the emergence of gram negative microorganisms, and to discover which factors make a small proportion of PD patients to be more prone to develop ESI of whatever origin.