Background: There is increasing concern about discontinuity of care across transitions (eg, from home to the hospital) and how it might affect appropriate medical management. Methods: We examined changes over time in outpatient-to-inpatient continuity of care in individuals hospitalized with advanced lung cancer and its relationship to end-of-life intensive care unit (ICU) use via retrospective analysis of the linked Surveillance, Epidemiology, and End Results–Medicare database. Patients were 21 183 Medicare beneficiaries 66 years or older and diagnosed as having stage IIIB or IV lung cancer between January 1, 1992, and December 31, 2002, who died within a year of diagnosis. Outpatient-to-inpatient continuity of care was defined as an inpatient visit by the patient’s usual care provider during the last hospitalization. The primary outcome measure was ICU use during the last hospitalization. Results: Outpatient-to-inpatient continuity decreased from 60.1% in 1992 to 51.5% in 2002 (P < .001). Factors associated with decreased continuity included male sex, black race, low socioeconomic status, being unmarried, treatment by a hospitalist, and treatment in a teaching hospital. Use of the ICU increased by 5.8% per year from 1993 to 2002. After adjustment for patient characteristics, patients with outpatient-to-inpatient continuity of care had a 25.1% reduced odds of entering the ICU during their terminal hospitalization. Conclusions: Outpatient-to-inpatient continuity of care declined during the 1990s and early 2000s. Patients with terminal lung cancer who experienced outpatient-to-inpatient continuity of care were less likely to spend time in the ICU before death.