The purpose of the study was to examine cognitive development (using the Bayley MDI) and mother–child interaction (using the Emotion Availability Scales, 3rd edition) among infants of opioid‐abusing mothers. Participants were 87 dyads (15 opioid‐exposed, 15 maternal depression and 57 unexposed mother–infant dyads). The study group included 15 infants (mean age=7.0 months, sd=2.8 months) of mothers who participated in buprenorphine‐replacement therapy. Study variables were evaluated during the second half of the first year and compared with the infants of depressed (mean age = 8.06 months, sd =2.4 months) and nonabusing mothers (mean age = 9.96 months, sd =2.9 months). The opioid‐exposed infants earned the lowest Bayley‐II MDI scores. Furthermore, they scored the lowest in infant involvement. The role of environmental risk factors, in turn, was highlighted in that the opioid‐abusing mothers scored the lowest in maternal sensitivity, structuring and nonintrusiveness. Maternal childhood foster care and criminal record were significantly related to lower sensitivity and higher intrusiveness. Finally, the environmental risk status of the opioid‐exposed infants was further underlined in that there were more separations from the mother in the end of the first year as well as an elevated risk for physical abuse.