Purpose: The objectives of this study were to investigate the current breast feeding rates in Jeju Province and to identify factors which influence breast feeding duration after birth. Method: The subjects were 189 women with a child between 12 months and 24 months old. Data was collected using a structured questionnaire from October 2003 to January 2004. Measures used in this study included general characteristics, delivery related characteristics, breast feeding related characteristics and the feeding type over a 12-month period after birth. Result: The study showed that the breast feeding rate in the first month was 63.1%, later dropping to 30.9% in the sixth month. In addition, only 14.2% of subjects were still breast feeding the baby at twelve months of age. The mean of breast feeding duration was 4.77 months. The factors which influenced breast feeding duration were wanted pregnancy, breast feeding education, planning of breast feeding and breast feeding experience. Conclusion: Considering the low rate of long-term breast feeding, the importance of breast feeding should be emphasized to promote and support the continuation of breast feeding in addition to at its initial stage. Based on the results, programs on breast feeding promotion and continuation need to be developed.