Purpose: The purpose of this study was to investigate the effects of using a Coaching Program on Comprehensive Lifestyle Modificationwith pregnant women who have gestational diabetes. Methods: The research design for this study was a non-equivalent control groupquasi-experimental study. Pregnant women with gestational diabetes were recruited from D women’s hospital located in Gyeonggi Provincefrom April to October, 2013. Participants in this study were 34 for the control group and 34 for the experimental group. The experimentalgroup participated in the Coaching Program on Comprehensive Lifestyle Modification. The program consisted of education, smallgroup coaching and telephone coaching over 4weeks. Statistical analysis was performed using the SPSS 21.0 program. Results: Therewere significant improvements in self-care behavior, and decreases in depression, fasting blood sugar and HbA1C in the experimentalgroup compared to the control group. However, no significant differences were found between the two groups for knowledge of gestationaldiabetes mellitus. Conclusion: The Coaching Program on Comprehensive Lifestyle Modification used in this study was found to be effectivein improving self-care behavior and reducing depression, fasting blood sugar and HbA1C, and is recommended for use in clinicalpractice as an effective nursing intervention for pregnant women with gestational diabetes.