Malassezia furfur has been increasingly associated with Broviac-catheter-related sepsis in infants receiving fat emulsions for parenteral alimentation. We examined by scanning electron microscopy the appearance of M. furfur attached to Broviac catheter segments mock-infected in vitro and to Broviac catheters removed from two infants with catheter-related sepsis. In vitro attachment occurred equally on external and internal surfaces of the catheters. Although some organisms were attached next to surface defects in the catheters, we could not determine if such defects were preferential sites of attachment. In the patient catheters, a dense coating of yeast cells was found adhering to the luminal surface, most abundantly near the tip. No organisms were seen on the external surface of the catheters. These findings show the need to examine the mechanisms of intraluminal catheter colonization in order to understand better the pathogenesis of M. furfur infections.