OBJECTIVE: Early detection and treatment of local oral fungal infection (OFI) minimize the risk of overgrowth and more serious complications such as invasive infections. Generalized fungal infection increases both morbidity and mortality in end-stage renal disease (ESRD) patients. This study reports the prevalence of ongoing OFI in patients with ESRD and presents correlations with dental microbial plaque formation and mouth dryness. It also describes how oral fungal growth correlates with oral lesions associated with fungal infection. MATERIAL AND METHODS: From March 2007 to October 2008, 93 ESRD patients and 45 age- and gender-matched controls were consecutively asked to participate in the study. In total, 34 patients were treated with peritoneal dialysis (PD) and 59 with haemodialysis (HD). OFI was diagnosed by taking two smear layers from the buccal mucosa. The samples from each side of the mouth were stained with the periodic acid Schiff (PAS) method. The associations between histological findings, age, gender, type of dialysis treatment, tobacco habits, self-experienced mouth dryness, taste disturbances, dental plaque and gingivitis were investigated. The presence of erythematous oral stomatitis, membranous candidiasis and angular cheilitis was noted to clarify how the presence of fungal hyphae correlate with oral lesions associated with OFI. RESULTS: OFI was found in 32% of the ESRD patients and 11% of the controls (p=0.007). An extensive OFI, defined as frequent fungal hyphae formations in oral mucosal smear layers, was found in 3% of the PD and 17% of the HD patients. Oral lesions, defined as clinical signs associated with OFI such as erythematous oral stomatitis, membranous candidiasis or angular cheilitis, were found in 37% of the patients with OFI, while 5% of the patients without findings of fungal infection presented oral lesions associated with OFI (p=0.0002). Furthermore, patients with self-reported mouth dryness were three times more likely (p=0.02) to be diagnosed with OFI. CONCLUSIONS: ESRD patients are found to have significantly more OFI than controls. Patients with ESRD experiencing mouth dryness and dental plaque formation also seem to be at risk of developing OFI. Detection of oral lesions associated with OFI should be combined with a histopathological diagnosis before antifungal treatment.