PURPOSE: This study aimed to validate the internal consistency of the Persian version of the diabetes distress scale-17 (DDS-17) and to investigate the prevalence of diabetes distress (DD), depression, and possible relevant factors. METHODS: This was a cross-sectional study on 820 diabetes patients (62.4 % females) in Tehran, Iran between January and June 2017. The Ethics Committee of Shahid Beheshti University of Medical Sciences approved the protocol. Patients filled out a demographic and health survey, DDS-17, the Beck Depression Inventory Second Edition (BDI-II) and the Summary of Diabetes Self-Care Activities Measure (SDSCA). DDS-17 consist of emotional burden, and physician, regimen, and interpersonal related distress. The correlation between DDS subscales and association between DDS and BDI-II or SDSCA scores were assessed using SPSS. RESULTS: The mean age was 58.91 ± 12.35 years. Majority of patients had high DD (37.2 %) and severe depression (38.7 %). The general and specific diets got the highest score in six SDSCA subscales. The Persian version of DDS-17 had excellent internal consistency with Cronbach's alpha coefficient of 0.924. The DDS score had significant relationship with socioeconomic level ( < .001), type of DM ( < .001), type of treatment ( < .001), glycemic control status ( < .001), complication ( < .001) and depression level ( < .001). The level of hemoglobin A1c was the most useful predictor of DDS score ( < .001). CONCLUSIONS: High prevalence of depression and distress in patient with diabetes calls for greater emphasizes on the importance of enhanced physicians and patients' knowledge in these areas.