Knowledge about the impact of maternal food and micronutrient supplementation on infant micronutrient status is limited. We examined the effect of maternal food and micronutrient supplementation on infant micronutrient status in the Maternal and Infant Nutrition Interventions in Matlab Trial. Pregnant women (n = 4436) were randomized to Early or Usual promotion of enrollment in a food supplementation program. In addition, they were randomly allocated to 1 of the following 3 types of daily micronutrient supplements provided from wk 14 of gestation to 3 mo postpartum: 1) folic acid and 30 mg iron (Fe30Fol); 2) folic acid and 60 mg iron; or 3) a multiple micronutrient including folic acid and 30 mg iron (MMS). At 6 mo, infant blood samples (n = 1066) were collected and analyzed for hemoglobin and plasma ferritin, zinc, retinol, vitamin B-12, and folate. The vitamin B-12 concentration differed between the micronutrient supplementation groups (P = 0.049). The prevalence of vitamin B-12 deficiency was lower in the MMS group (26.1%) than in the Fe30Fol group (36.5%) (P = 0.003). The prevalence of zinc deficiency was lower in the Usual food supplementation group (54.1%) than in the Early group (60.2%) (P = 0.046). There were no other differential effects according to food or micronutrient supplementation groups. We conclude that maternal multiple micronutrient supplementation may have a beneficial effect on vitamin B-12 status in infancy.