Purpose: This study was done to identify that Rooming-in of new mothers have an influence on continuous breast feeding. Method: This is a comparative survey study which was done by self reported questionnaire and telephone contacts. The subjects are collected from two groups which consist of 29 in Rooming-in group and 24 in Non-Rooming in group respectively. The data were collected method of this study was lists of given to mothers while they were in the hospital and interviews by telephone were done at their home 3 months and 6 months after delivery. Result: The results of this study were as follows: 1. The rates of breast feeding were 79.3% in the Rooming-in group and 41.7% in the non-Rooming in group after 3 months. There was a statistically significant difference between the two groups ($X^2$=10.217, p=.009). 2. The rates of breast feeding were 69.0% in the Rooming-in group and 29.2% in the Non-Rooming-in group at 6 months. There was a statistically significant difference between the two group ($X^2$=10.310, p=.012). Conclusion: Rooming-in system provoke an increase of the breast feeding rate in new mothers and encourage them to keep breast feeding. In addition, it would be desirable that hospitals apply Rooming-in system actively and encourage new mothers to breast feed for 24 hours a day. It could be make breast feeding successful.