Objectives: The present study examined the psychometric properties of the Persian version of the OARS multidimensional functional assessment questionnaire (MFAQ/OARS) in Iranian elderly. Methods: This non-experimental psychometric study utilized the Persian translated questionnaire based on the IQOLA protocol. The study cohort was selected from the comprehensive healthcare centers across Kashan, Iran in 2016, based on the interviews with 482 adults ≥ 60-year-old (269 men and 213 women). The face validity of the questionnaire was assessed according to the experts' opinions, while the content validity was assessed using the Lawshe and Bausell-Waltz methods. The concurrent validity and inter-rater reliability were assessed for each of the five domains of functioning. Test-retest reliability was assessed using the Intraclass Correlation Coefficient (ICC). Results: The questionnaire exhibited adequate face validity. The Lawshe and Bausell-Waltz methods revealed a 98% content validity estimation of the items, and those with lower values were maintained in the questionnaire after necessary modifications. The MFAQ/OARS was correlated with the WHODAS 2.0 and the GDS15 (P < 0.0001), which indicated the acceptable concurrent validity of the questionnaire. All domains of the questionnaire showed satisfactory inter-rater reliability estimates, and the ICC was > 0.89 for all domains except for the activities of daily living (ICC=0.78). The test-retest reliability for the five domains was 0.72-1. Discussion: According to the study results, the Persian version of MFAQ/OARS presented a satisfactory face, content, and concurrent validity, and reliability for functional assessment among Iranian elderly. Therefore, it can be used in clinical fields and research studies to assess the functioning of elderly in various life domains.