Conflict among couples was examined following a transition to parenthood intervention to determine both short-term efficacy of the program and elucidate the process of change postintervention. A randomized clinical trial design was used to examine conflict in couples who participated in a transition to parenthood psycho-educational workshop compared with controls. The beginnings of improved communication in conflict were evident at 3 months postbirth through decreased husband contempt and increased husband positive affect during conflict in a sample that demonstrated more substantial improvement at 1 year postintervention. Increases in husband positive affect in the workshop group at 3 months postbirth predicted more positive and less negative wife affect during conflict at 1 year postbirth. Results suggest that some indicators of intervention efficacy were evident, postintervention change can be gradual, husbands may be more receptive to implementing change shortly after birth, and early changes can be associated with later positive outcomes. Findings have implications for preparing couples for the gradual and complex nature of change associated with intervention.