The authors compared through the most common clinical indexes the periodontal conditions of a group of type I and type II diabetic patients with those of a group of healthy control subjects. Results showed the existence of statistically significant differences for each parameter considered (plaque index, gingival index, bleeding index, attachment loss). Also with comparable oral hygiene diabetics showed a worse periodontal condition in comparison with controls. In absolute terms type II diabetics presented worse clinical index scores compared to type I diabetics even if not at a statistically significant level.