-RESUScitation Project (NCT02837497, 2016–2021). Setting: Eighteen PICUs. Patients: Children less than or equal to 18 years old and greater than or equal to 37 weeks postconceptual age receiving chest compressions (CC) of any duration during the study. Interventions: None Measurements and Main Results: Of 1,100 children with IHCA, there were 273 medical cardiac (25%), 383 surgical cardiac (35%), and 444 noncardiac (40%) cases. Favorable neurologic outcome was defined as no more than moderate disability or no worsening from baseline Pediatric Cerebral Performance Category at discharge. The medical cardiac group had lower odds of survival with favorable neurologic outcomes compared with the noncardiac group (48% vs 55%; adjusted odds ratio [aOR] [95% CI], aOR 0.59 [95% CI, 0.39–0.87], p = 0.008) and surgical cardiac group (48% vs 58%; aOR 0.64 [95% CI, 0.45–0.9], p = 0.01). We failed to identify a difference in favorable outcomes between surgical cardiac and noncardiac groups. We also fa