Data on pediatric critical care in Iran are insufficient. This study was performed to determine the outcomes and characteristics of critically ill children admitted to a pediatric intensive care unit (PICU) in Ahvaz, Iran. A retrospective study was conducted among all patients in the PICU of Abuzar Hospital for one year. Their medical documents were reviewed. A total of 400 patients were identified. The average age of patients was 29.94±39.55 months, and 53.8% of them were males. Nearly half of the cases were under age one. The most prevalent causes of PICU admission were respiratory (36.5%), neurological (18.5%), and infection-related diseases (15%). Besides, 55.7% of patients (n=223) had no history of underlying health problems. Admissions were more frequent in winter (n=125; 31.3%) and spring (n=101; 25.3%). The mortality rate and the mean hospital length of stay (LOS) were 15.5% and 10.79±6.39 days, respectively. In addition, 231 patients had an abnormal respiratory rate and a quarter of them (n=97) required ventilation support. Moreover, 377 and 82 patients were malnourished and severely underweight, respectively. A significant association was found between the mortality of patients and malnutrition, as well as having consanguineous parents (P<0.001). The death rate was significantly higher in patients with infectious disease than non-infectious, as well as in long-stay PICU patients than in short-stay patients (P<0.05). Additional studies are required to find factors contributing to the disease burden among PICU patients in Iran to develop appropriate therapeutic strategies and improve the outcomes of pediatric patients.