Background: Pregnancy was found to be a significant triggering factor for smoking cessation and the reduction of nicotine consumption, but 50 - 70 % of mothers who stopped smoking during pregnancy resume tobacco smoking after delivery. One main reason for the high relapse rates is that many women are solely motivated to quit smoking for the baby’s sake. After birth, the external reason for having quit has vanished and no other internal or external motives exist for many women to maintain being smoke-free. Therefore, under consideration of the Transtheoretical Model approach, relapse prevention and smoking cessation interventions have to focus on two aspects: (1) on a specific reformulation of the stages of change for women who show a temporarily and externally motivated change in smoking behavior during pregnancy, (2) on intervention strategies taking advantage of the behavioral change already done and evoking the cognitive and behavioral processes necessary for maintenance. In Germany pediatricians are in a unique position to address this issue because nearly every mother attends a pediatric practice for preventive examination of the newborn. Objectives: To adapt and implement motivational enhancement interventions in pediatric practices. The aim is to examine the effectiveness of a modified stage-matched motivational enhancement intervention added to the common pediatricians´ advice. A second aim is the reformulation and reassessment of the stages of change for women who have recently given birth. Methods: The study design is a randomized controlled trial. Mothers smoking at the beginning of the pregnancy and attending pediatric practices in West Pomerania will be assigned to an intervention group (n = 330) and referred to a liaisonal service providing a face-to-face motivational enhancement intervention followed by telephone brush-up sessions. A control group (n = 330) receives treatment from the pediatrician as usual at the preventive examination. The core outcome measures comprise abstinence, and progress in the stages of change 6, 12, 18 and 24 months after baseline. Expected impact: Data will evaluate the usefulness of intervening in pediatric offices and will provide information about a tailored intervention program. The processes of change favorable for intervention in this population will be identified. This is of great relevance with regard to the prevention of health damage for mother and child. Furthermore, results will serve as a basis for guidelines for pediatricians to deal with women smoking postpartum. Relationship to the objective of the collaboration: As in the other studies, this study provides empirical data of a new proactive approach to reach underserved populations in the addiction field. This project will add knowledge on how to intervene (motivational enhancement vs. usual advice), on setting-specific advantages of pediatric offices and on the impact of the chosen intervention strategy.