This study examined the factor structure of the Centers for Epidemiologic Studies Depression Scale (CES-D) in a sample of 40,403 African American women participating in the Black Women's Health Study (BWHS). To examine within group differences in the structural characteristics of the CES-D, women were stratified by age (< 60 vs. > or = 60 years). Confirmatory factor analysis indicated that a four-factor solution was a good fit for the data in both groups. The four factors extracted (depressed, somatic, positive, and interpersonal) matched findings from previous studies in other populations. Although item loadings were identical for 19 of 20 items, when equality restrictions were placed on factor loadings, the factors were not shown to be equivalent across groups. The only observed difference in item loadings was that the item "people disliked me" loaded higher on the interpersonal factor for younger women than older women. The variance/covariance matrix differed between groups. The correlations between the depressed and somatic factors were identical for the two age groups. However, correlations among the other factors were weaker among older women. We conclude that four-factor structure of the CES-D is supported for African American women, but the relationships among the factors vary with age.