The aim of the study is to examine effects of a program for enhancing parent-child interaction on mother's parenting stress whose child has a difficult personality, and a general mother-child interaction. The subjects of the study were mothers and their children in three and four full age in a regular child care whose difficult personality caused parenting stress. The program was modified as a group program by applying activities for parent-child interaction enhancement based on the therapeutic play theory. It was conducted twice a week for 10 times and each session was comprised of 60 minutes. The data process was made as follows. Changes in parenting stress were examined by using the scores of the parenting stress scale before and after the program. During the program, each session and free play of the children and mothers were recorded to examine changes in parent-child interaction. The recorded material was evaluated by the interaction behavior rating scales for each mother and child.. The results of the study are as follows. First, mother's parenting stress was reduced after completing the program. Second, as the session advanced, pleasure and positive response increased in mother-child interaction. Positive behavior in interaction during the program increased due to an increase of the mother-child physical contact and simulated compliment. Although the study was a short-term case study of a relatively small number of participants with limitations for a generalization, the results of the study showed that the parent-child interaction enhancement program had a positive effect on reducing mother's parenting stress and improving mother-child interaction.