Adolescent childbearing is a major concern because of the associated negative health, social, and economic consequences. To determine whether teenagers are using organized family services to prevent unwanted pregnancies, the National Reporting System for Family Planning Services began in 1972 to collect information on family planning clinic patients in the United States, Guam, Puerto Rico, and the Virgin Islands. Family planning visits to private physicians were excluded from the survey. Since 1977 the survey has included only those visits made for medical services associated with family planning; visits made for replenishing contraceptive supplies, counseling, pregnancy, or venereal disease tests were excluded. The 1978 survey consisted of a sampling of 1,195 randomly selected sites and a systematic selection of visits based on a proportion of each site's reported annual number of visits, and its geographical location. This report of the 1978 survey provides a descriptive analysis, with tables and graphs, of the teenagers under study. The following areas are presented: social and demographic characteristics; pregnancy history; contraceptive utilization and sources of method; contraceptive method switching; and teenagers compared with older women. The appendices provide technical notes discussing survey methodology, data collection and processing, and the reliability of estimates; definitions of terms used in this report; and a copy of the Clinical Visit Record which was used to collect survey data. (WAS)