A notable omission in studies of developmental links to early nutritional deficiencies is infant attachment. In those few studies investigating associations between infant nutrition and attachment, nutrition was defined solely by physical growth, and infants had moderate-severe growth retardation. In this study, we utilized multiple markers of infant nutrition. Our sample consisted of 172 12-month-old Peruvian infants and their mothers from low-income families, with a follow-up assessment on 77 infants at 18 months. Infants were not severely malnourished, but did have micronutrient deficiencies. Anthropometry, dietary intake, and iron status were used as measures of infant nutrition. Based on infant behavior in a structured laboratory situation, Q-sort techniques were used to rate three attachment markers: infant secure base behavior, interaction quality, and negative emotionality with mother. At 12 months, infant weight was positively related to interaction quality. At 18 months, infant iron status was positively related to secure base behavior. This pattern of findings remained even after statistically controlling for family socioeconomic status and maternal education. Our findings indicate that infant nutritional status is associated with markers of infant attachment and these associations are not restricted just to severely malnourished infants.