We performed hemoglobin electrophoresis in 30,400 apparently healthy black individuals in the Washington D.C. Metropolitan area, who were participating in a community based sickle-cell screening program during the period 1978-1985. The overall prevalence of sickle-cell trait was 6.7%. The frequency of sickle-cell trait in various age groups, which included young children, adults, and individuals over 65 years of age, ranged from 6.4 to 7.4%. There were no statistically significant differences in the prevalence of sickle-cell trait among the various age groups, nor did we detect a significant trend for increasing or decreasing sickle cell frequency with advancing age (P = 0.418). Thus, in this population sickle-cell trait appears to have no effect on longevity. If the various complications of sickle-cell trait reported in the literature are not fortuitous, their frequency and/or severity must be too low to affect prevalence figures.