In Saudi Arabia, the prevalence of diabetes mellitus (DM) is high. DM is a risk factor for periodontal disease. The current study aimed to estimate the prevalence and potential associated factors for periodontitis among type I and II DM patients in Abha, Saudi Arabia. A cross-sectional study was conducted among patients with DM who attended the Periodontal Consultant Center at King Khalid University and Aseer Central Hospital, in Abha city, from January 2020 to January 2022. A questionnaire was used to collect relevant data. Patients were assessed for the severity of periodontitis. A total of 499 DM patients were enrolled in this study. The prevalence of periodontitis was 7.4% among type I DM and 46.4% among type II DM patients. The prevalence of periodontitis was significantly associated with age among type I DM patients (p-value = 0.001) and type II DM patients (p-value = 0.001), respectively, and smoking among type I DM patients (p-value = 0.002) and among type II DM patients (p-value = 0.000), respectively. Age and smoking were the potential associated factors for the prevalence of periodontitis among type I and II DM. The study provides evidence about the prevalence of periodontitis among DM patients, creates awareness regarding the factors that potentially contribute to worsening periodontal tissues, and the importance of early diagnosis and prevention to avoid the irreversible destruction of the periodontal tissues.