The study evaluated the effect of motherhood in adolescence on emotional availability in mother-infant interaction, considering maternal attachment Internal Working Models. Participants were 50 adolescent mother-infant dyads (maternal age range = 15-21 years olds) and 50 adult mother-infant dyads (maternal age range = 25-40 years olds). At infant 3 months, mother-infant interaction was video-recorded and coded with the Emotional Availability Scales and the Adult Attachment Interview was administered to the mothers. Analysis showed that adolescent mothers were less sensitive, more intrusive and hostile and less adequate in scaffolding their infant's orientation towards objects than adult mothers; infants of adolescent mothers were less involved and responsive towards their mothers than infants of adult mothers. No interaction effect between maternal age and maternal attachment on maternal and infant emotional availability was found. The results suggest that early motherhood is an important risk factor for the quality of the emotional availability of mother and infant at three months, showing with respect to other studies that the poor involvement and the low responsiveness of the infant is also correlated to young maternal age in that period.