Extensive population surveys begun in Italy in 1943 revealed a high incidence of mycrocytemia. Health authorities established a national organization to combat microcytemia which financed and directed activities throughout Italy from 1955 to 1971. The work performed by the microcytemia centers in screening and prophylaxis is described. The results of a screening program underway since 1967 involving 46,559 students of the University of Rome are presented in detail. A preliminary survey of 256 families revealed that the incidence of subsequent births after the births of a child affected by Cooley's anemia was generally low. Results obtained to date are encouraging and justify more extensive programs for the prevention and treatment of microcytemia.