The glucose concentration in unstimulated mixed saliva and serum was assayed and correlated with oral candidal colonization in 41 diabetics and 34 healthy control subjects. In diabetic patients, salivary glucose concentration was significantly higher than in the controls and was directly related to blood glucose concentration. Although the difference in the frequency and quantity of oral candidal isolation failed to reach significance between the two groups, diabetic patients who carried Candida intraorally had significantly higher salivary glucose concentrations than those in whom Candida could not be isolated.