Background: Diabetes mellitus (DM) is one of the three most common chronic diseases worldwide. This study aimed to determine the prevalence of diabetic polyneuropathy (DPN) among patients with diabetes.Method: This cross-sectional study was carried out on DM patients who visited King Abdulaziz University Hospital (KAUH) between August 2021 and February 2022. We used the Michigan Neuropathy Screening Instrument (MNSI) questionnaire to determine if the patients had DN. In addition, we used the Global Physical Activity Questionnaire (GPAQ) to assess the level of physical activity (PA) in these DM patients.Results: A total of 336 patients consented to participate in the study. We found a DN prevalence of 23.8% amongst DM patients treated at the KAUH. In addition, the prevalence of DN amongst T1DM and T2DM patients was found to be 16% and 24.4%, respectively. Furthermore, we found that 65% of DM patients developed complications, with a significant correlation observed between the duration of DM and the development of complications. However, patient age and sex were non-statistically significantly correlated with the development of complications. Analysis of the GPAQ showed that among the 249 patients who completed the questionnaire, none had a high physical activity level, while 4% and 96% had moderate and low physical activity levels, respectively. No association was found between physical activity and patients' age, sex, type of DM, duration of DM, and development of complications.Conclusion: DN prevalence amongst DM patients treated at KAUH was 23.8%. The duration of diabetes was found to be a risk factor for DN. However, patient age and sex were non-statistically significantly associated with DN.