Abstract Objectives Intensivists and subspecialists often collaborate in diagnosing patients in the pediatric intensive care unit (PICU). Our objectives were to characterize critically ill children for whom subspecialty consultations were requested, describe consultation characteristics, and determine consultations’ impact on PICU diagnosis. Methods We performed a retrospective study using chart review in a single tertiary referral PICU including children admitted for acute illness. We collected data on patients with and without subspecialty consultations within the first three days of PICU admission and determined changes in PICU clinicians’ diagnostic evaluation or treatment after consultations. Results PICU clinicians requested 152 subspecialty consultations for 87 of 101 (86%) patients. Consultations were requested equally for assistance in diagnosis (65%) and treatment (66%). Eighteen of 87 (21%) patients with consultations had a change in diagnosis from PICU admission to discharge, 11 (61%) attributed to subspecialty input. Thirty-nine (45%) patients with consultations had additional imaging and/or laboratory testing and 48 (55%) had medication changes and/or a procedure performed immediately after consultation. Conclusions Subspecialty consultations were requested during a majority of PICU admissions. Consultations can influence the diagnosis and treatment of critically ill children. Future research should investigate PICU interdisciplinary collaborations, which are essential for teamwork in diagnosis.