The prevalence of denture stomatitis as well as the frequency of isolation of Candida species and their density on the palatal mucosa have been compared in 70 acrylic denture-wearers suffering from non-insulin-dependent diabetes mellitus (NIDDM) versus 58 acrylic denture-wearers with normal glucose metabolism. The adherence of C. albicans to palatal epithelial cells in vitro was also assessed in both groups. The patients with NIDDM had a significantly higher prevalence of denture stomatitis compared with the controls. The frequency of Candida colonization was increased in diabetics, but not significantly. According to the imprint culture technique, the density of Candida species was significantly higher in patients with NIDDM compared with the controls. The adherence of C. albicans to palatal epithelial cells from patients with NIDDM showed a significant increase compared with that observed in cells collected from the controls. This study supports the view that NIDDM predisposes to Candida-associated denture stomatitis.