Introduction: Type 1 diabetes (DM1) affects the metabolism of glucose, lipids and proteins and increases the risk of periodontal disease. The aim of this research was to identify the periodontal characteristics of patients diagnosed with DM1. Materials and methods: the study examined 35 patients with DM1, who were given a complete periodontal exam; fasting values of glycated hemoglobin (HbA1C) and glycemia were taken and the data were analyzed both descriptively and comparatively against the periodontal clinical parameters and the periodontal diagnosis. Results: the prevalence of chronic periodontitis was 74.3% and of gingivitis, 25.7%. The average value of glycated hemoglobin (HbA1C) for patients diagnosed with gingivitis was 9.15, while for patients with periodontitis it was 8.375, without being statistically significant. Average periodontal clinical attachment loss was 3.15mm, while the average number of teeth lost was 6.91 for the entire population. The patients with periodontitis presented greater clinical attachment loss and pocket depth. Conclusions: the patients with DM1 had periodontitis or gingivitis, confirming their susceptibility to periodontitis, and they should therefore take care to receive regular gingival and periodontal check-ups.