The medical costs associated with cancer treatment have increased rapidly in Japan; however, little data exist on actual costs, especially for end-of-life care. Therefore, this study aimed to examine the medical costs of lung cancer patients during the last 3 months before death and to compare the costs with those of initial anticancer treatment. We retrospectively evaluated all patients who died from lung cancer at the Japanese Red Cross Medical Center between 1 January 2008 and 31 August 2019. Patients were classified into three cohorts (2008-2011, 2012-2015 and 2016-2019) according to the year of death; the medical costs were evaluated for each cohort. Costs were then divided into outpatient and inpatient costs and calculated per month. Seventy-nine small cell lung cancer and 213 non-small cell lung cancer patients were included. For small cell lung cancer and non-small cell lung cancer patients, most end-of-life medical costs were inpatient costs across all cohorts. The median monthly medical costs for the last 3 months among both small cell lung cancer and non-small cell lung cancer patients did not differ significantly among the cohorts, but the mean monthly costs for non-small cell lung cancer tended to increase. The monthly medical costs for the last 3 months were significantly higher than those for the first year in SCLC (P=0.013) and non-small cell lung cancer (P<0.001) patients and those for the first 3 months in non-small cell lung cancer patients (P=0.005). The medical costs during the end-of-life period for lung cancer were high and surpassed those for initial treatment.