Objective: To assess whether the maternal consumption of milk and milk product s affects development of cow’s milk (CM) antibodies in infants. Design: A rando mized pilot trial using food frequency questionnaires (mothers) and food records (infants). Setting: Families with a newborn infant with increased HLA-DQB1-co nferred risk of type 1 diabetes and at least one first-degree relative affected by type 1 diabetes from 16 hospitals in Finland between April 1995 and November 1997. Subjects and intervention: Infants randomized to receive a hydrolysed for mula when breast milk was not available during their first 6-8 mo (n = 112). Of these, 13 dropped out by the age of 3 mo and two were excluded due to incomplet e CM antibody data. Results: Maternal milk protein intake from cheese during pre gnancy was inversely related to IgA-class antibody titres to beta-lactoglobuli n (BLG) and casein (CAS) at 3 mo, and to IgA antibody titres to BLG at 6 mo. Mat ernal consumption of raw milk products during lactation was positively related t o the development of IgA antibody titres to CAS at 6 mo, and inversely correlate d to IgG antibody titres to bovine serum albumin (BSA) and IgA antibody titres t o CAS at 2 y. Maternal cheese consumption was inversely related to the IgG antib ody titres to CM formula and CAS and to the IgA antibody titres to CAS in early infancy. Conclusions: Few associations were established between maternal CM prot ein intake and CM protein antibody levels in the infants. The milk and milk prod ucts taken by the mother differed in their impact on the emerging CM antibody re sponse in the offspring. Objective: To assess whether the maternal consumption of milk and milk product s affects development of cow’s milk (CM) antibodies in infants. Design: A rando mized pilot trial using food frequency questionnaires (mothers) and food records (infants). with a newborn infant with increased HLA-DQB1-co nominally risk of type 1 diabetes and at least one first-degree relative affected by type 1 diabetes from 16 hospitals in Finland between April 1995 and November 1997. Subjects and intervention: Infants randomized to receive Of these, 13 dropped out by the age of 3 mo and two were excluded due to incomplet e CM antibody data. Results: Maternal milk protein intake from cheese during pregnancy was inversely related to IgA-class antibody titres to beta-lactoglobuli n (BLG) and casein (CAS) at 3 mo, and to IgA antibody titres to BLG at 6 months. Mat ernal consumption of raw milk products du ring lactation was positively related to the development of IgA antibody titres to CAS at 6 mo, and inversely correlate to IgG antibody titres to bovine serum albumin (BSA) and IgA antibody titres to CAS at 2 y. Maternal cheese consumption was inversely related to the IgG antibodyters titres to CM formula and CAS and to the IgA antibody titres to CAS in early infancy. Conclusions: Few associations were established between maternal CM prot ein intake and CM protein antibody levels in the infants. The milk and milk prod ucts by the mother differed in their impact on the emerging CM antibody re sponse in the offspring.