Obstetric delivery is the most frequent cause of hospital admission in the United States, reflecting the approximately 4 million births in this country each year (1). Because of steadily increasing hospital costs, overall lengths of hospital stay have declined. To assess national trends in length of stay for hospital deliveries, data were analyzed from CDC's National Hospital Discharge Survey (NHDS) from 1970 through 1992, by method of delivery. This report summarizes the results of the analysis.