OBJECTIVE: Pediatric extracorporeal membrane oxygenation (ECMO) varies in the way care is provided from hospital to hospital. This variability in hospital ECMO care can be represented by the variation in ECMO costs. We hypothesized that hospitals will demonstrate large variations in case-mix-adjusted ECMO inpatient costs for children requiring ECMO and higher volume hospitals will have lower associated costs. METHODS: We retrospectively analyzed the inpatient cost of children receiving ECMO in 2006, 2009 and 2012, using the Healthcare Cost and Utilization Project Kids' Inpatient Database. We used a hierarchical linear regression model and the intraclass correlation coefficient to quantify how much of the difference in ECMO inpatient costs was associated with the hospital where a child received care. To do this, we adjusted for patient factors, hospital factors and potentially modifiable factors such as complications, procedures and length of stay. RESULTS: The median inflation-adjusted inpatient costs for children requiring ECMO were $183,000, $240,000 and $241,000 in years 2006, 2009 and 2012, respectively. The largest median cost for ECMO cases in a given hospital in a given year ($690,000) was more than 11 times that of the smallest median cost ($60,000). After case-mix adjustment, 27% of the variation in inpatient costs was associated with the hospital where ECMO care was provided. Average hospital costs were not associated with hospital ECMO volume. CONCLUSIONS: The large variation in ECMO inpatient costs between hospitals suggests great variation in care between hospitals, which is important because hospitals have a co-existing variation in ECMO survival rates.