OBJECTIVES Functioning in severe mental disorders is very important and brief rating instruments are needed. Personal and Social Performance Scale (PSP) is one of the instruments which can be used in severe mental disorders in a short time. METHODS The study was performed in the psychiatry departments of two university hospitals. In- or outpatients diagnosed as schizophrenia or bipolar disorder were included in the study. Exclusion criteria were comorbidity of other psychiatric disorders (including substance use disorders) and physical diseases. For concurrent validity, besides PSP, Clinical Global Impression (CGI), Global Assessment of Functioning (GAF) of DSM-IV, Quality of Life and Satisfaction Questionnaire (QLS-Q), and Positive and Negative Schizophrenia Scale (PANSS) were used. For discriminant validity, the mean scores of PSP of patients with and without symptomatic remission were compared. RESULTS The study was carried out with a total of 135 patients, 105 (77.8%) diagnosed as schizophrenia and 30 (22.2%) diagnosed as bipolar disorder. The mean age of the patients was 34.1±10.7 and 75 (55.6%) of them were male. The duration of illness was 10.4±7.5 years. The mean score of PSP was 60.0±17.1. In the reliability analysis, the Cronbach alpha coefficient was 0.8327, and item-total score correlations were between 0.4920-0.7462. In the validity analyses, the total score of PSP was significantly correlated with the total score of CGI (r=-0.854, p<0.0001), GAF (r=0.748, p<0.0001), QLS-Q (r=0.734, p<0.0001), and PANSS (r=-0.664, p<0.0001). The difference between the patients with and without symptomatic remission was significant (54.8±14.8 vs. 72.6±9.8, t=7.434, p<0.0001). CONCLUSIONS The Turkish version of PSP was found to be reliable and valid in severe mental disorders. It can be used both in clinical trials and routine follow-up.