Purpose: This study was done to develop a sexual health education program for unmarried mothers that were intended to provide the correct sexual knowledge, to help them establish positive sexual perception and to improve sexual health. The program was applied and its effect was evaluated. Method: One group pretest-posttest quasi-experimental research design was applied to evaluate the effect of a sexual health education program unmarried mothers. The research team developed a 34 hour program of 16 units, where the basic schemes were human development, relationships, personal skills, sexual behavior, sexual health, and society & culture. We applied the program to 32 unmarried mothers in the Institute for unmarried mothers in Gangwon-do, Korea from April 19, 2004 to June 14, 2004. Result: After the application of an 8 week sexual health education program, the subjects significantly showed a better perception of self-efficiency, self-esteem, sexual knowledge and sexual behavior than before the program. Conclusion: The sexual health education program for unmarried mother in this study was effective on improving sexual perception and promoting sexual health behavior.