Intensive care units (ICUs) are increasingly used for hospital care, yet out-of-pocket spending for ICU hospitalizations remains poorly understood, particularly among the nearly half of the US population with commercial health insurance. Using 2008-19 MarketScan data, we compared 1,441,810 hospitalizations involving ICU services with 13,011,208 hospitalizations that did not involve ICU services. Average cost sharing, adjusted for patient and admission factors, increased from $1,137 per hospitalization in 2008 to $1,539 in 2019, or a 34 percent increase. This was driven by increasing deductibles, which rose by 163 percent. Across twenty clinical conditions whose hospitalizations commonly occurred in both ICU and non-ICU settings, ICU admission was associated with $155 higher cost sharing (13.0 percent higher) relative to cost sharing in non-ICU hospitalizations. Patients with high-deductible plans faced the highest cost sharing relative to those with other plan types. Patients who received out-of-network hospital care encountered higher cost sharing relative to those admitted to in-network hospitals with in-network clinicians.