PURPOSE:To define organizational culture in hospitals that have received quality certificates and to identify attitudes of healthcare personnel toward change. METHODS:The population was all physicians and nurses (N=3,067) employed at four private hospitals that have received accreditation or the "ISO" certificate, and four public hospitals, all of which were located within Istanbul city limits. A proportional sample of 570 participants were selected from the eight hospitals. Data-gathering tools were information form, culture scale, and Attitude Against Change Scale (AACS). Data were evaluated by using descriptive statistics, Cronbach alpha coefficient, Chi-square test, and by t test for dependent groups, one-way variance analysis (ANOVA), and Tukey test. FINDINGS:The lowest score averages on the AACS were found in those employed in public hospitals, in those who perceived top executives as autocrats, and in those who were unwilling to participate in quality studies. Participants in a power culture were least open to change. CONCLUSIONS:A collaborative culture was the most evident culture in private hospitals, but in public hospitals the most dominant culture was a power culture.