Abstract Physical inactivity has been viewed as an emerging public health problem in developing countries including Ethiopia. Diabetes mellitus (DM) is a group metabolic disorder characterized by chronic hyperglycemia resulting from defects in insulin secretion, function, or both. Its prevalence increases with changing lifestyles including physical inactivity across the globe. However, there is limited research, and not yet received attention in Ethiopia. This study aimed to assess the prevalence and associated factors of physical inactivity among adult diabetic patients in Felege Hiwot Referral Hospital, Bahir Dar, Northwest Ethiopia. An institutional-based cross-sectional study design was conducted among 308 participants from February to June 2018 at Felege Hiwot Referral Hospital. A face-to-face interview was conducted using a structured questionnaire by trained data collectors. Participants were selected through a systematic random sampling technique. Physical inactivity was assessed by the international physical activity questionnaire (IPAQ). Collected data were entered in Epi info version 7 and transferred to SPSS version 20 for analysis. A summary of descriptive statistics and multiple binary logistic regression analyses were computed to identify associated factors of physical inactivity among adult diabetic patients. P