The study compared hemoglobin (Hb) and serum ferritin levels between adolescent and adult women with different body mass indices, dietary intake, and sociodemography. A secondary analysis of data for 3177 South African women ⩾15 years of age who participated in the SANHANES-1 study was undertaken. Abnormal Hb (≤12 g/dL) and serum ferritin (<15 μg/mL) were based on the World Health Organization's criteria for nonpregnant women aged ⩾15 years. Data were analyzed using STATA version 11. Overall, anemia was detected in 740 (23.3%) participants. Of the individuals in the subsample (n = 1123, 15-35 years) who had serum ferritin measured, 6.0% presented with iron depletion (ID) and 10.8% presented with iron-deficiency anemia (IDA). The highest prevalences of anemia, ID, and IDA were in 15- to 18-year-olds (11.2%, 8.8%, and 20.2%, respectively). Black young adults (19-24 years) were up to 40 times more likely to present with ID compared with their non-black counterparts. While overweight adolescents were three times more likely to be anemic, overweight and obese young adults, as well as obese older adults (25-35 years), were less likely to be anemic compared with normal-weight women of all age groups. Overconsumption of dietary fat increased ID by up to 54- and 11-fold (adolescents and 25- to 35-year-olds, respectively). In South Africa, anemia is most prevalent in adolescents and black women. Anemia is also an indicator of overconsumption of dietary fat and a marker of socioeconomic disadvantage.