The aim of the present study was to demonstrate that mother avoidance in infants at the age of 12 months can be predicted by the infants' differential vocal engagement to mother versus a female stranger at the age of 3 months. Differential engagement in favor of the mother was supposed to relate to low future avoidance. The vocal behavior of 26 infants was assessed during face-to-face interactions with their mothers and with a strange woman at the age of 3 months. Differential vocal engagement was measured in terms of the time difference the infants spent vocalizing during eye contact with mother and stranger. At the age of 12 months avoidance of the mother was assessed during the reunion episodes of Ainsworth's Strange Situation. The result confirmed the assumption. Differential engagement in 3-month-olds is discussed as an indicator of the early infant–mother relationship.