The International Clearinghouse for Birth Defects Monitoring Systems (Clearinghouse) was created as a monitoring network aimed at exchanging epidemiological data on malformations in newborns. After several years of experience, directors of two programs participating in this network describe some rather unknown aspects of this membership. Firstly, a short description is given of these two different programs: one located in France (Rhone-Alpes/Auvergne) which is regional and population-based and collects information on birth defects, and one located in Spain which is nation-wide, hospital-based and collects iuformation on birth defects and controls. The Clearinghouse membership gives the possibility to utilize a data base more effectively by receiving external material with which to compare local data, being given advice from experts in case of clusters, and conducting international collaborative studies, examples of these activities are given. The international contacts established through the Clearinghouse are looked upon as educational, and may actually increase the possibility of detecting risk factors for birth defects and eventually preventing them.