Candida biofilms on indwelling devices are an increasing problem in patients treated at intensive care units. The goal of this study was to examine the occurrence and frequency of these biofilms. A total of 172 catheters were collected from 105 male and 67 female patients (the age range of both patient groups was from 3 weeks to 98 years old). The catheters were incubated on blood agar plates and the resulting yeast colonies were subsequently identified. Furthermore, pieces of catheters were fixed, dried and sputter coated with gold for investigation with scanning electron microscopy (SEM). Yeasts were recovered from significantly more catheters obtained from men than from women (chi(2): n = 67; P < 0.01). In SEM, 56.4% catheters turned out to be positive for biofilm formation. Again catheters from male patients were statistically significant (chi(2): n = 40; P < 0.01) more often positive than those from women. Candida albicans (71.1%) was the most common species isolated from the catheters, followed by C. glabrata (10.3%), C. parapsilosis (8.2%) and C. tropicalis (5.2%). Based on the results of this investigation, the epidemiology of Candida biofilms on indwelling devices seems to be a promising target for future investigations.