Background: Immunotherapy has emerged as a pivotal component in the treatment of cancer, particularly owing to the progress made in targeted therapies. Our analysis aimed to quantify the disparities in access to immunotherapy and the associated outcomes. Methods: We used National Inpatient Sample data (2017-2020) to identify patients hospitalized with a primary diagnosis of antineoplastic immunotherapy, stratifying them by either Medicaid or private insurance. The aim was to determine disparities in the likelihood of immunotherapy across various demographic factors and differences in outcomes, such as mortality and healthcare resource utilization. Results: A total of 14,530 patients were hospitalized for antineoplastic immunotherapy, with 2,960 (20%) having Medicaid insurance and 7,760 (53%) having private insurance. Patients with Medicaid were younger than those with private insurance (17.22% vs 38.53%). Compared to Medicare, patients with private insurance were more likely to undergo immunotherapy (OR=2.65(2.31-3.04); p<0.001), while those with Medicaid had decreased odds (OR=0.75(0.61-0.92); p=0.007). Older patients were less likely to undergo immunotherapy than younger patients (36-45: OR=0.69(0.56-0.85), p=0.001; 46-64: OR=0.7(0.59-0.82), p<0.001; >65: OR=0.48(0.4-0.59), p<0.001). Compared to the White population, Hispanics (OR=1.3(1.12-1.51); p<0.001) and patients of other races (OR=3.33(2.86-3.88); p<0.001) had increased odds of undergoing immunotherapy, while Black patients had decreased odds (OR=0.43(0.35-0.53); p<0.001).The individuals with the highest median income were found to have the highest likelihood of undergoing immunotherapy (>$86,000, OR=2.23(1.92-2.59); p<0.001), followed by those in the less income groups ($65,000-$85,999: OR=1.6(1.38-1.86), p<0.001; $50,000-$64,999: OR=1.48(1.28-1.73), p<0.001). Patients in medium-sized (OR=1.27(1.03-1.55); p=0.022) and large (OR=3.49(2.93-4.15); p<0.001) hospitals were more likely to receive immunotherapy compared to those in small hospitals. Patients with Medicaid had a higher total hospitalization cost than those with private insurances (+$219,484(83,731-355,238); p=0.002). There was no observed difference in mortality rates among patients with Medicaid or private insurance who received immunotherapy (Medicaid: OR=0.86(0.1-6.98), p=0.88; Private: OR=0.67(0.11-3.96), p=0.66). Conclusions: The utilization of immunotherapy among Medicaid patients is found to be lower when compared to those with private insurance and Medicare. This disparity is also related to a higher overall cost of hospitalization in Medicaid patients. However, there was no difference in mortality between the different insurance types who received immunotherapy.