Mortality trends in the United States from 1950 through 1986 were analyzed for the conditions that are or have recently been among the six leading causes of death. The age-adjusted mortality rate for all causes has decreased from 841.5 to 541.7 per 100 000 population. Cause-specific, age-adjusted mortality rates have declined from 1950 through 1986 for cerebrovascular disease, injuries, perinatal conditions, heart disease, and influenza and pneumonia. Time trends in the proportion of persons dying of each of these diseases, however, have varied; the proportion dying of cerebrovascular disease, injuries, and perinatal conditions has decreased, and the proportion of persons dying of heart disease and influenza and pneumonia has remained fairly stable from 1950 through 1986. During this same time, age-adjusted death rates have increased for chronic obstructive pulmonary disease and have remained fairly stable for malignant neoplasms, while the proportions of persons dying of chronic obstructive pulmonary disease and malignant neoplasms have increased dramatically. For people aged 35 to 64 years, malignant neoplasms have now overtaken heart disease as the leading cause of death. For those aged 65 years and older, heart disease remains the leading cause of death, accounting for almost 50% of all deaths in persons 85 years and older.