The aim was to evaluate the effects of a family-focused early intervention programme on the cognitive, motor, and language development of infants exposed to social and biological risks in the first year of life. Quasi-experimental randomized controlled trial (RBR-6ct969), with intervention (IG; n = 72) and control (CG; n = 170) groups. IG mothers participated in two individual Newborn Behavioral Observation sessions and six in-group sessions. Children's development was assessed at 4, 6, 9, and 12 months of age, using the Bayley-III scale. The results showed that IG children had higher receptive language scores (p = 0.02) and lower gross motor scores (p = 0.03) than CG. The chance of receptive language delay (OR = 0.61, CI 0.38-0.96, Cohen's d = 0.28) was reduced in IG, but no impact was observed on the other domains. The present intervention reduced the risk of receptive language delay, despite its low intensity and short duration.