this study aimed to compare clinical characteristics, evolution and severity of adult patients admitted in public and private intensive care units. it is a retrospective, longitudinal and quantitative analysis of 600 patients admitted in four intensive care units of s？o paulo, brazil. differences were found between patients admitted in private and public hospitals regarding the following variables: age, origin, length of stay and mortality in the critical unit, cardiac, hematological, neurological and kidney failures and some comorbidities. the results reveal the importance of analyzing in detail clinical characteristics and healthcare of patients admitted in public institutions, because of the high mortality found. the intensive care nurse can contribute to change this scenario, because she/he has a leadership role in planning and provision of resources for intensive care.