Purpose: To investigate if patients with periodontitis attending the Dental School in Huddinge, Sweden presented with more signs of systemic diseases, such as cardiovascular disease, diabetes mellitus and respiratory diseases, compared to healthy and gingivitis patients. Materials and Methods: In this retrospective study, dental charts were examined where the periodontal diagnoses of patients were known. A total of 325 patients with severe periodontitis and 149 patients without periodontitis, born 1928 to 1968, were identified. Diagnosis regarding the systemic diseases was self-reported. Odds ratios for cardiovascular diseases, diabetes mellitus and respiratory diseases were calculated with a logistic regression model that was adjusted for age, gender and smoking. Results: It was observed that more cases of periodontitis were found in older individuals than the controls (61.7 vs 56.2 years; P 0.001). A total of 44.3% of patients with severe periodontitis also suffered from cardiovascular diseases, 19.1% respiratory diseases and 21.2% from diabetes mellitus. Among the controls, 30.9% had cardiovascular disease, 23.5% suffered from respiratory diseases and 6.7% had diabetes mellitus. Across both groups, hypertension was the most frequent diagnosis. There was a significant association between periodontitis and cardiovascular disease (odds ratio [OR] = 1.79, confidence interval [CI] 1.12-2.86), but not between respiratory diseases and periodontitis (OR = 0.88, CI 0.53-1.47). The risk of diabetes mellitus was greater among those patients with periodontitis (OR = 2.95, CI 1.45- 6.01). Conclusion: This study found that patients with periodontitis presented with more systemic diseases, such as cardiovascular disease and diabetes mellitus than control patients. However, no association was found between periodontitis and respiratory diseases. At the present time, the reasons for the associations or lack of association are unknown. Keywords: register study, risk factor, periodontal disease, Sweden, systemic diseases