Objectives: The purpose of this study is to assess disability among older persons, 60 years old or older, helping policy makers and program planners concerned elderly issues to provide proper services.

Methods & Materials: The study included 600participants were chosen in a systemic classified cluster using 36-Item Interviewer Administered, without day codes version of world health organization disability schedule II (WHODAS II). It was assessed by comparing the converted points of the initial five scale points into one hundred scale points as the algorithm method presented by the WHO. Data analyzed by SPSS 11.5 with Chi- square, Mann- Whitney and Kruskal- Walis tests.

Results: Mean score of disability among older persons was 33.3(SD=25.9), men 33.0(SD=28.1) and women 33.6(SD=23.8). There was no significant difference on mean scores between men and women (P>0.05), but there was significant difference between age groups (P<0.05). Mean scores increased dramatically with increasing age groups. The greatest scores belonged to domains; Getting around, Life activities and Participation in society respectively.

Conclusion: In comparison with other research the mean score of disability among older persons who lived in Tehran was high, especially in domains has mentioned above. Therefore it is necessary to pay more attention to prevention and treatment of diseases, disorders and impairments which caused disability on the right time. Also it is required to provide aid equipments and physical adaptation to decrease disability in the elderly.