Since screening of newborn infants for phenylketonuria (PKU) by Guthrie bacterial inhibition assay was established in the 1960s, 2 556 498 infants have been tested in Australia. Two hundred and twenty-two cases of PKU, and five cases of the variant forms of malignant hyperphenylalaninaemia (MHPA) have been found over this period, an incidence of 1/11 516 for PKU, and 1/511 300 for MHPA. In 1979, 18 infants with PKU and one with MHPA were detected. Screening for congenital hypothyroidism was carried out in four centres, and 28 new cases were detected in 1979 (an incidence of 1/5746).