Since screening of newborn infants for phenylketonuria (PKU) by Guthrie bacterial inhibition assay was established in the 1960s, 2779 790 infants have been tested in Australia. Two hundred and forty cases of PKU (rate: 1/11 582) and six cases of the variant forms of malignant hyperphenylalaninaemia (MHPA) (rate: 1/463 298) have been detected. In 1980, 18 infants with PKU were detected. Screening for congenital hypothyroidism was carried out in six centres, and 40 new cases were detected in 1980.