Adult height has been positively associated with the risk of breast cancer in a number of recent investigations. The authors assessed height in relation to breast cancer risk in a case-control study of US black women aged 25-69 years; 674 hospital patients with newly diagnosed breast cancer and 1,155 controls hospitalized for nonmalignant conditions unrelated to height were interviewed. After control for multiple confounders, the relative risk estimate for women < 61 inches (< 154.9 cm) tall was 0.5 (95% confidence interval (Cl) 0.3-0.7) relative to the median height of 64-65 inches (162.6-165.1 cm). Among women > or = 61 inches (> or = 154.9 cm) tall, there was little indication of any variation in risk with increasing height. The findings suggest that short stature is associated with a decreased risk of breast cancer in US black women.