In screening programmes testing newborns for galactose-1-phosphate uridyltransferase and/or galactose, partial enzyme deficiency is frequently discovered. This is shown for one laboratory in Switzerland where 104 newborns were singled out from a total of 476,000. Of these, 72 had partial transferase deficiency below 9 mumol/h per g Hb and were assumed to be compound heterozygotes for "classical" galactosemia and the Duarte variant. Present day management of compound heterozygotes consisting of lactose-free diet for 4 months is described and discussed in the light of published opinion. The appropiateness of this pragmatic approach can at present not be judged according to objective criteria.