Activities of daily life are basic components of life which reflect an important aspect of functional independence in the elderly. The aim of this study was to develop an up to date and culturally appropriate scale to assess activities of daily lives of the Iranian elderly. Research method was descriptive-analytic and the statistical population consisted of elderly men and women (over 60 years old) residing in Arak and Shazand cities in 1391. The sample consisted of two groups including 297 subjects (exploratory factor analysis) and 280 subjects (confirmatory factor analysis) who voluntarily participated in the study. Exploratory and confirmatory factor analysis and principle component analysis with varimax rotation were used for data analysis. All statistical operations were performed with SPSS-16 and LISREL software. Exploratory factor analysis extracted 5 subscales including gross activities (9 items), personal activities (7 items), religious and social activities (8 items), fine activities (4 items), and machine washing (2 items). Confirmatory factor analysis findings confirmed these results as well. These five factors explained 75.90% of total variance (first factor 50.38%, second factor 11.06%, third factor 6.30%, forth factor 4.675%, and fifth factor 3.485%). This instrument was named "the Elderly's Activities of Daily Life Scale (Iran-ADLS)". The scale was filled out twice by 30 subjects (50% women) with 1 to 2 weeks of interval and Pearson correlation coefficient was 0.76 to 0.97 for 1 to 5 subscales and 0.97 for the total score of the scale, indicating a good to excellent test-retest reliability. Also, internal reliability was calculated with Chronbach's alpha (0.96) indicating an excellent internal reliability for this scale. Totally, these results confirmed that "the Elderly's Activities of Daily Life Scale" was a valid and reliable instrument to measure the elderly's ability and disability.