Introduction: The aim of this study is to adapt the Rivermead Mobility Index (RMI) into Turkish and to test its validity and reliability. Materials and Method: After the translation procedure, reliability was assessed with test-retest technique to determine the stability of measure. Reliability was also assessed using KR-20 reliability coefficient to examine internal consistency. Validity was assessed with known-groups technique using student t test and also with comparing known disability instruments using Pearson's correlation coefficient to examine construct validity. The study was undertaken in two different settings, one was an institution where healthy and frail elders live together and the other was the region of a primary health care center which is in the service of elders living at home. Ambulatory (n= 112) and bedbound (n= 37) elders living institution and community-dwelling elders (n= 245) selected randomly. Results: Test-retest reliability coefficient (r=0.98) (p<0.001), and KR-20 reliability coefficient (r = 0.91) (p<0.001) was high and known-groups validity was statisticaly significant (p<0.001) and RMI score was correlated with Brief Disability Questionnaire-BDQ (r = 0.66) (p<0.001) score. Conclusion. The Turkish version of RMI seems to be reliable and valid measure of mobility disability in elderly people.