A randomized controlled trial (RCT) compared two groups of mother-infant dyads in a Stockholm sample. One had received mother-infant psychoanalytic treatment (MIP group) and the other Child Health Center care (CHCC group). Effects were found on mother-reported depression and expert-rated mother-infant relationship qualities and maternal sensitivity. When the children were 41/2 years old, they were followed up with assessments of attachment representations, socioemotional development, and global functioning. They also were divided into two types according to individual characteristics and psychological well-being: the ‘OK’ and the ‘Troubled’ children. Of 80 dyads in the mother-infant RCT, data were gathered from 66 cases approximately 31/2 years after treatment. The children in the MIP group had better results on global functioning. There were more OK children in the MIP group and more Troubled children in the CHCC group. No other between-group differences were found. A relatively brief mother-infant psychotherapy seemed to help the children function better and be less troubled 31/2 years after therapy.