Background: Immune checkpoint inhibitors (ICPis) have shifted the landscape of cancer treatment from conventional cytotoxic regimens. The mechanism of action involves suppression of immunologic checkpoints that often results on a unique spectrum of side effects associated with immune-mediated inflammations. The Aim of this study is to evaluate the financial impact from immune-related adverse events (IrAEs) reflected in hospitalized patients undergoing anti-neoplastic immunotherapy using the data from a nation-wide database. Methods: We performed retrospective analysis with the National Inpatient Sample (NIS) using ICD10-CM and PCS codes to identify patients with solid tumors hospitalized for immunotherapy between October 2015 and 2018. Inpatient data from patients with or without having developed IrAEs during the hospitalizations were compared in this study. IRAEs included systemic symptoms, diarrhea/colitis, hepatic and endocrine adverse events. Baseline characteristics and inpatient complication variables were collected and analyzed between these two groups. Results: From 5,795 admissions of ICPi-treated cancer patients, 1,160 patients or 20 % of these hospitalizations presented with IrAEs, females represented (37.5%) with an age of 57 years though not statistically different from admissions without IrAE. On the other hand, length of stay was statistically longer (7 vs 5 days, p < 0.05) with higher admission expenses ($184,255 vs $ 133,305, p < 0.05) from IRAE-associated admissions. Higher IrAEs were observed among patients who were ICPi-treated for genitourinary (GU) cancers (22% vs 15%, p < 0.05). IRAE as an independent risk factor was associated with higher costs even when adjusted for other risk factors, significantly contributed to a higher admission expenses by a coefficient at $46,624 (SE +/- $13,943). Conclusions: Although ICPi-therapies have offered various clinical benefits among cancer patients. They have also contributed to both direct and indirect costs of cancer management. Our analysis showed a higher IrAE incidence associated with ICPi-treated GU cancer patients, patients who developed IRAEs had a longer hospital stay and higher in-hospital mortality, resulting in higher care expenses as one of the indirect financial burdens of ICPi therapies, no differences were observed between gender, race, or income.