A systematic follow-up of children diagnosed as deaf may reveal additional pertinent information which may be instrumental in ascertaining the cause of deafness. 107 deaf children were detected by a prospective study of 62 000 children screened for deafness during 11 years. The cause of deafness could be determined in 63 children while in 44 no etiology was apparent. Investigation of the 44 children revealed a genetic origin of deafness in 12 additional children. Consanguinity was evident in the children whose deafness was of genetic origin. Identification of the cause of deafness in children contributes to prevention of this handicap.