PURPOSE: This study was conducted to evaluate the effectiveness of the maternal role education program for primiparas in mother-infant interaction, childrearing environ- ment, and infant development. METHOD: A Non-equivalent control group time-series design was used. For the intervention group, programmed parenting education focusing on mother-infant interaction, home environment for infant development, and parent counseling and support was provided via home visits or telephone for twelve months. RESULT: Significant differences were found in the mother-infant interaction feeding scale at one and three months, but no differences were found in the teaching scale at six and twelve months between the intervention and control groups. Also, the difference in childrearing environment (HOME) between the two groups was significant at three, six, twelve months. In addition, the intervention group showed higher GQ in the Griffiths mental development scale at three and six months. In multiple regression analysis, 22.6% to 43.6% of infant development was explained by HOME, mother-infant interaction, and previous development. CONCLUSION: The maternal role education program proved to be effective in promoting mother-infant interaction, organizing the childrearing environment, and fostering infant development.