Objective To evaluate the effects generated by an intensivist in pediatric intensive care unit (PICU) on the process of care and patient outcomes. Methods This study was a retrospective observational study conducted in the 16-bedded PICU of a tertiary referral center. Two years (2013-2015) period of the PICU without an intensivist and the following two years (2015-2017) when it was attended by an intensivist who was also the first ever graduate of the fellowship program in Turkey were compared. Results Number of patients followed in PICU increased more than 2-fold. Number of mechanically ventilated patients increased more than 2-folds and presence of intensivist reduced the mechanical ventilation duration by 59%. Presence of intensivist reduced the mortality rates by 2.18 times. It was shown that management of PICU beds by an intensivist resulted in increased number of patients per year per PICU bed, increased care of true critical care patients who are in need of more intensive therapies and invasive procedures including extracorporeal treatment options, decreased length of stay, decreased number and rate of nosocomial infections, and decreased mortality rate. Conclusions What transforms a unit full of critically ill patients to an intensive care unit is a dedicated intensivist. The current study demonstrated that intensivist is the crucial component of the PICUs.