The National Center for Health Statistics (NCHS) has been operating a reporting system for family planning clinic services since May 1969. Data are collected through this system about individuals who receive family planning services from participating family planning service sites throughout the U.S. and some of its territories. The information obtained is useful for research purposes and for program planning and evaluation, primarily at the national level. The information obtained through the National Reporting System may be divided into 4 general types: data about the participating facilities, data about the sociodemographic characteristics of the individuals being served, data about the types of services being provided, and data about the visits made. Information collected about the individuals being served consists of identification information and the sociodemographic characteristics of each person. Data about the family planning services provided refer to the medical, counseling, and referral services that each person receives at a particular visit and include information about the type of contraceptive method adopted by each person and previous contraceptive use. Focus here is on the legislative and historical background of the reporting system, the provisional reporting system (the report form, operational procedures, and output tabulations), and the national reporting system (the report forms, operational procedures, and output tabulations). The 100% family planning reporting system has grown rapidly during the 7 years of its operation. During 1970 some 800 service sites reported serving 415,000 patients who made 640,000 visits for family planning services; these figures have increased to 4940 service sites reporting 3,248,000 patients who made 5,853,000 visits during 1975.