Background: Immunotherapy harnesses cancer patients’ immune systems to eradicate cancer cells, and has become the standard of care as first line or combination therapy in advanced lung cancer. While immunotherapy is more tolerable than other treatments such as chemotherapy, a minority of patients experience toxicities requiring clinical intervention. The aim of this study is to examine the risk of all-cause inpatient and emergency department visits among lung cancer patients diagnosed with cancer receiving immunotherapies as first line treatments using a linked population dataset. Methods: We analyzed administrative data from N = 3,268 lung cancer patients diagnosed between 2013 and 2018 from the Immunotherapy, Palliative and End-of-life Treatment Utilization and Spousal Outcomes (ImmPETUS) cohort, a linked population-based cohort of melanoma, lung, breast, colorectal and bladder cancer patients and their spouses in Utah. Analyses were conducted with multivariable logistic regression models in R and adjusted for sex, age, age at diagnosis, cancer stage, race, ethnicity, marital status, neighborhood education and household income, insurance type, rurality and comorbidity. Results: Among patients diagnosed with lung and bronchus cancers (53.1% male, 46.9% female), 9.5% received immunotherapy as a first line treatment and 57.3% had distant stages at diagnosis. Adjusting for race, ethnicity, neighborhood education and income, and rurality, lung cancer patients who received immunotherapies as a first course of treatment had greater odds of all-cause emergency department encounters (aOR = 1.94, 95% CI = 1.49-2.53, p < 0.001) compared to patients receiving other first line treatments. Non-Medicaid patients and patients with greater comorbidities were less likely to have all-cause emergency department encounters (aOR = 0.66, 95% CI = 0.53-0.82, p < 0.001; 0.92, 95% CI = 0.89-0.96, p < 0.001) and all-cause inpatient visits (aOR = 0.60, 95% CI = 0.46-0.77, p < 0.001; aOR = 0.89, 95% CI = 0.85-0.93, p < 0.001) compared with Medicaid patients and patients with no comorbidities. Nonmarried patients (aOR = 0.71, 95% CI 0.59-0.86, p < 0.001) were less likely to have all-cause inpatient visits compared with those who were married/partnered. Conclusions: Our findings support that patients receiving immunotherapies as first line treatment have increased risk of all-cause emergency department encounters. This analysis of real-world data enabled the examination of downstream healthcare utilization outcomes of immunotherapy cancer patients within Utah, and provides insight into groups at risk for adverse events. Future directions include examining the clinical and social pathways of these disparities, such as immune-related adverse events, access to supportive care, and supports for patient and family decision making.