Compared 48 families of nonorganic failure to thrive (NOFT) infants with those of 52 physically healthy infants of similar demographic characteristics using the Family Environment Scale (FES). Families of NOFT infants had more problematic relationships as indicated by lower scores on the Family Relationships Inventory (FRI) components of the FES, including lower Cohesion and Expressiveness, than families of physically healthy infants. Contrary to predictions, families did not differ in level of Conflict or Organization. Families of NOFT infants had lower intellectual and Cultural Orientation. These findings suggest that problematic intrafamilial relationships are associated with NOFT and may influence the psychological outcomes of children with this condition. Studies are needed to document the effects of family functioning on the physical growth and psychosocial development of NOFT children.