Between 1990 and 1996 we coordinated a Quality Control (QC) Program in Parasitology directed to Public Health Institutions in Spain. Periodically, parasited specimens, mainly feces or blood, were sent to Microbiology Laboratories for identification. Each QC was accompanied by a short clinic and epidemiological information in order to help in the diagnostic approach. After the answers to the QC were received a bulletin that included the solution to the QC, comments on the several answers received and a chapter with parasitological themes related with the QC, was sent to each participating Laboratory. The bulletin was accompanied by a card that included a photograph and a short description of the organism object of the QC.