Both negative and idealized maternal prenatal representations may constitute a risk for mother-infant interaction. This study analyzed the role of maternal prenatal representations and pre- to postnatal representational change in predicting mother-infant emotional availability (EA) among 51 drug-abusing mothers and their infants who participated in either psychodynamic group therapy (PGT) or received psychosocial support (PSS) and among 50 nonusing comparison dyads. Maternal representations of her child, the child's father, her own mother, self-as-mother, and self-as-woman were measured during pregnancy and at 4 and 12 months' postpartum with the Interview of Maternal Representations (M. Ammaniti et al., 1992; M. Ammaniti, R. Tambelli, & P. Perucchini, 1998). EA was measured with the Emotional Availability Scales, fourth edition (Z. Biringen, 2008) at 4 and 12 months. The results showed that drug-abusing mothers had more negative prenatal representations of the self-as-woman and of the child's father. Postnatally, PSS mothers tended to first idealize their child, but later to experience disillusionment of idealization. Both negative and idealized prenatal representations of the self-as-mother predicted mother-infant EA problems, but only among the PGT mothers. For all mothers, negative representational change was detrimental for the mother-infant EA whereas for drug-abusing mothers, also increasing idealization from the prenatal period to the postnatal period was harmful. Clinicians working with drug-abusing mothers should aim at supporting the development of a realistically positive view of motherhood.