The aim of this study was to describe the psychometric properties of the Farsi form of the Kessler Psychological Distress Scale (K10). The translated Farsi Form of the K10 was used, and administered to a total of 128 Iranian psychiatric outpatients from Tehran. One-week test-retest was 0.85 indicating its high temporal stability. Cronbach’s alpha value and Spearman-Brown coefficient of the K10 reached 0.92, Split-Half 0.85, indicating its good internal consistency. The K10 correlated 0.73with the General Health Questionnaire (GHQ-12), 0.80 with the Beck Depression Inventory (BDI-13), 0.29 with the Beck Hopelessness Scale (BHS), 0.42 with the Beck Suicidal Ideation Scale (BSIS), and 0.62 with the Wish to be Dead Scale (WDS) indicating good criterion-related validity. Finally, a principal axis analysis with Varimax rotation was carried out. Two factors were extracted, accounting for 73.22% of the total variance. These factors were labeled: Anxiety (59.07%), and Depression (14.65%). The results indicate that the K-10 administered to this Iranian sample yields good internal consistency, temporal stability, criterion-related validity and a two-factor structure reflecting important features of psychological distress. In general, the K10 could be recommended in research on anxiety and depression among Iranian psychiatric outpatients.