Objectives: The purpose of this study was to investigate the effect of a child-parent secondhand smoke(SHS) prevention program(C-PSHSPP). Methods: The participants were parents whose children were attending daycare centers located in S city. The institutions were selected using two-stage cluster sampling and data were collected using a structured questionnaire. Descriptive statistics were performed using SPSS version 18.0. Results: Number of cigarettes smoked per day, rate of smoking when with child decreased significantly. Parental awareness on SHS and scores on changes of experiential process increased significantly. Conclusions: From these results, it is suggested that the C-PSHSPP has beneficial effects in decreasing parental daily smoking amount at the same time increasing parental awareness on SHS and importance of smoking cessation. Therefore, C-PSHSPP can be recommended as a SHS intervention program for preschool children.