We used capture-recapture methodology to estimate total deaths and efficiency of reporting for 2 systems. During 1987-1992, there were 165 measles-associated deaths in the multiple-cause mortality database at the National Center for Health Statistics (NCHS) and 184 reported to the measles surveillance system at the National Immunization Program (NIP). We estimated that 259 measles deaths actually occurred; the reporting efficiencies were 64% for the NCHS and 71% for the NIP. Overall the death-to-case ratio was 2.54 and 2.83 deaths/1000 reported cases, using the NCHS and NIP data, respectively. Pneumonia was a complication among 67% of measles-related deaths in the NCHS data and 86% of deaths in the NIP data. Encephalitis was reported in 11% of deaths in both databases. Preexisting conditions related to immune deficiency were reported for 16% of deaths in the NCHS system and 14% in the NIP; the most common was human immunodeficiency virus infection. Overall, 90% of deaths reported to the NIP occurred in persons who had not been vaccinated against measles. During 1993-1999, only 1 acute measles-related death was reported to the NCHS and no deaths were reported to the NIP. This is consistent with the extremely low reported incidence of measles in the United States during these years.