Purpose: The purpose of this study was to measure the effects of a breast feeding promotion program for working women on breast feeding continuation, mother-infant attachment, and maternal sensitivity. Methods: The design of this study is nonequivalent control group design with repeated measures. Results: There were significant differences in breast feeding continuation between two groups at each time point except 2 days and 1 week after delivery. The scores of mother-infant attachment and maternal sensitivity of experimental group were higher than those of the control group, but there were no significant differences between two groups. Conclusion: Although some modifications in contents and administration will be required to increase the effectiveness of the program, breast feeding promotion program for working women can be an effective nursing intervention which can facilitate breast feeding continuation and mother-infant relationships.