Chronic obstructive pulmonary disease (COPD) and asthma are significant causes of illness and death in blacks. Racial differences in normal values of pulmonary function tests must be considered in both patient care and research. Assessment of risk factors is an important part of COPD management and prevention. An extensive review of data from the National Center for Health Statistics and from other population-based studies confirmed lower lung volumes in blacks compared to whites. However, the ratio of forced expiratory volume in 1 second to forced vital capacity was not lower in blacks; racial differences in flow rates were inconsistently reported. Thoracic dimensions were smaller in blacks than in whites in healthy populations. The cause and the physiologic and pathophysiologic significance of these racial differences are unknown. Population-based studies in blacks have firmly established only age and cigarette smoking as risk factors for COPD other than asthma. In 1987, 43% of black men aged 45 and older smoked cigarettes compared to only 30% of white men. Further research is needed on racial differences in pulmonary function and the effects of multiple risk factors to enhance understanding of COPD etiology and prevention. More vigorous smoking prevention and cessation efforts should be targeted for blacks by physicians and public health organizations.