Objective: This study is designed to evaluate the frequency of periodontal disease in a group of patients with type 1 diabetes mellitus and how this relates with diabetes metabolic control, duration of diabetes, and presence of diabetic complications. Methods: A comparison was made of periodontal parameters (plaque index, bleeding index, pocket depth and attachment loss) in a group of diabetic patients (n=90) versus a group of non-diabetics (n=90). Logistic regression analysis was performed to evaluate relationship between periodontal parameters and degree of metabolic control, the duration of the disease, and the appearance of complications. Results: Diabetics had greater bleeding index (p<0.01), deeper periodontal pockets (p<0.01) and more periodontal attachment loss (p<0.01) than non-diabetics. Deficient metabolic control and presence of diabetic complication were associated with higher bleeding index and pocket depth (p?0.02). Conclusions: Patients with type 1 diabetes appear to show increased periodontal disease susceptibility, particularly those with poorer metabolic control or with diabetic complications.