Objective: The aim of this study is to evaluate the reliability and validity of the Turkish version of the Recovery Process Inventory with a sample of people who have been diagnosed with mental illness. Methods: The study used a methodological design. Its sample included 220 people who have been diagnosed with mental illness. At first, the linguistic validity and the content validity methods were done. The scale's applicability and understandability was pilot tested. The data of the study were obtained from June 2018 to August 2018 by the Information Form, the Recovery Process Inventory (RPI) and the WHOQOL-8 Quality of Life Scale (WHOQOL-8 QLS) validity and reliability analyses were done. Results: The mean age of the patients was 38.13 +/- 12.07 years, 58.6% were women, 95.4% had health insurance, 50.5% of them do not work, 57.3% live with spouses and children, 48.6% have depression and 29.5% have anxiety disorder, 79.5% were not hospitalized. The mean score of the WHOQOL-8 QLS was 25.60 +/- 5.06 (range: 14-36). The KMO value subscales is seen that the sample is able to produce factor structure. Cronbach's alpha according to the subscale; 1) connected to others 0.54; 2) recovery/self-esteem 0.72; 3) living situation 0.67; 4) anguish 0.65; 5) others care/help 0.05; 6) hopeful/cares for self is 0.21. Item 7 (I do not take care of myself in any way) and item 10 (I get on with my life when I have hope) in the hopeful/cares for self-subscale reduced the value of Cronbach's alfa because these items were not culturally appropriate the Turkish population. Discussion: As a result of the validity and reliability analyses, it was determined that the RPI is a valid and reliable scale to measure subjective recovery in individuals who are diagnosed with mental illness. It has been suggested that the RPI should be applied to wider sample groups to investigate the instability of individuals who are diagnosed with mental illness.