More than 20% of US children between ages 2 and 5 years are overweight suggesting efforts to prevent obesity must begin earlier. This study tested the independent and combined effects of two behavioral interventions delivered to parents, designed to promote healthy infant growth in the first year. Mother-newborn dyads intending to breastfeed were recruited from a maternity ward. With a 2 × 2 design, 160 dyads were randomized into one of four treatment cells to receive both, one, or no interventions delivered at two nurse home visits. The first intervention ("Soothe/Sleep") instructed parents on discriminating between hunger and other sources of infant distress. Soothing strategies were taught to minimize feeding for non-hunger-related fussiness and to prolong sleep duration, particularly at night. The second intervention ("Introduction of Solids") taught parents about hunger and satiety cues, the timing for the introduction of solid foods, and how to overcome infants' initial rejection of healthy foods through repeated exposure. A total of 110 mother-infant dyads completed the year-long study. At 1 year, infants who received both interventions had lower weight-for-length percentiles (P = 0.009). Participants receiving both interventions had a mean weight-for-length in the 33rd percentile; in contrast, those in other study groups were higher first intervention only--50th percentile; second intervention only--56th percentile; control group--50th percentile).This suggests that multicomponent behavioral interventions may have potential for long-term obesity prevention (ClinicalTrials.gov number, NCT00359242).