Objective: Outcome of patients is determined not only by severity of illness index, but also by the impact of patients’ preadmission comorbid status. Therefore,weaimed at evaluating the outcome of patients treated in a pediatric intensive care unit, with special focus on the group of children with chronic diseases. Methods: Data were obtained prospectively and outcome was assessed according to the Pediatric Overall Performance Category scale for 449 patients in a pediatric intensive care unit of the Split University Hospital. Functional performance was assessed as the preadmission score and the discharge score in patients with neurodevelopmental disabilities, patients with other chronic diseases, and those without chronic disease. Results: The discharge functional statuswas significantly dependent on the preadmission functional status and on predicted mortality. Children with neurodevelopmental disabilities had the significantly worse baseline score and the significantly smaller deterioration of functional morbidity at discharge compared to children with no chronic disease and children with other chronic diseases. Conclusions: The Pediatric Overall Performance Category scale has proved its applicability in a small intensive care unit, with a heterogeneous population of patients. It should therefore be considered for regular evaluation of health care quality, as a simple and accurate tool. As opposed to other patients, functional status of children with neurodevelopmental disabilities was markedly influenced by their comorbidity. Their preadmission status was worse than the status of other children, and hence could not significantly deteriorate at discharge.