Background: The COVID-19 pandemic has derailed normal operations in the healthcare delivery systems in the US and globally, providing prioritized care to patients seeking acute management of the novel coronavirus and its complications. Simultaneously, cancer screening tests have decreased, resulting in decreased rates of cancer diagnoses and referrals to oncologists. The purpose of this study was to assess metastatic lung cancer-related and total healthcare resource utilization (HCRU) and costs during the pandemic/post-pandemic period compared with the pre-pandemic period. Methods: A retrospective claims study using de-identified medical and pharmacy insurance adjudicated claims from national and sub-national health plans and self-insured employer groups was initiated in patients greater than 18 years of age with commercial, commercial self-pay, and Medicare Advantage insurance. Analyses were conducted from January 1, 2019 to February 29, 2020, the pre-pandemic period, and compared to March 1, 2020 to April 30, 2021, the pandemic/post-pandemic period. Multivariable logistic regression models were used to assess the probability of having a hospital, ER or hospice/palliative visit. Multivariable linear regression models were used to see differences in the utilization of outpatient visits. Multivariable Generalized Linear Models with a log transformation and gamma distribution were used to see if there were differences in healthcare costs. Results: 3,230 (pre-pandemic period) and 2,922 (pandemic/post-pandemic period) patients with newly diagnosed metastatic lung cancer were included in the study. The mean age of the patients in the pre-pandemic period was 61.1 years and 61.3 years in the pandemic/post-pandemic period. The odds of receiving outpatient and inpatient hospice/palliative care, inpatient and ER care were lower in the pandemic/post-pandemic period. After controlling for all variables, (OR=0.813; 95% CI: 0.729, 0.906), p=0.0002. Per patient per month (PPPM) metastatic lung cancer-related and total costs were higher in the pandemic/post-pandemic time period. After controlling for all variables, (Cost ratio=1.059; 95% CI: 1.023, 1.096), p=0.0011. Conclusions: This is the first study assessing the impact of the COVID-19 pandemic on HCRU and costs in patients with newly diagnosed metastatic lung cancer.