A nonconcurrent prospective study in Washington County, Maryland, identified 4032 (1204 male, 2828 female) white persons aged 18 years and over who were enumerated in a 1963 nonofficial census and became widowed between 1963 and 1974, and an equal number of married persons, each matched to a widowed person as to race, sex, year of birth and geography of residence. All were followed to 1975, the date of a second census. Mortality rates based on person-years at risk were virtually no different for female widowed than married, but significantly higher for male widowed than married, even after adjustment for a number of demographic, socioeconomic and behavioral variables. The male widowed in all age groups experienced higher mortality than the male married, the relative risk attaining statistical significance only in age groups 55--64 and 65--74 years, although the indicated relative risk was even higher in the younger age groups. There was little evidence of higher mortality in the first or second six-month intervals following bereavement than in subsequent years for either sex, but a suggestively higher mortality in year 2 for female widowed under age 65 years.