This manuscript is a summary of a comprehensive report dealing with asthma and pregnancy issued by the working group on Asthma and Pregnancy, National Institutes of Health (NIH), National Heart, Lung, and Blood Institute. The report was developed by a panel of obstetricians, pharmacologists, internists, allergists, and pulmonologists, who met over an 18-month period under the auspices of the NIH. Undertreatment of pregnant asthmatics, partially because of unfounded fears of adverse pharmacologic effects on the developing fetus, remains the major problem in the management of asthma during pregnancy in the United States. The four key components of asthma management during pregnancy are: 1) objective assessment of maternal lung function and fetal well-being, 2) avoidance or control of environmental precipitating factors, 3) pharmacologic therapy, and 4) patient education.