Purpose: This study was conducted to develop a health education program for preschoolers who have defected from North Korea with their mothers, and to evaluate the effects on health knowledge and behavior. Methods: A non-equivalent control group pre-post test design was used with 58 preschoolers who were assigned to either the experimental or control group (29 for each group). The program was composed of five sessions in health education and contracts. To test the effectiveness of the intervention, health knowledge and behaviors, and total bacterial colony counts on hands were measured at one pretest and two post tests (1 week and 4 weeks after the intervention ended). Data were analyzed using the SAS program. Results: Health knowledge and behavior in the experimental group increased significantly compared to the control group. The effects of the intervention were evident even at 4 weeks after the intervention ended. Total bacterial colony counts in the experimental group decreased significantly at the 1 and 4 week posttest intervention compared to the control group. Conclusion: Results indicate that this program is effective in improving health knowledge and behavior in these children and therefore can be utilized to ensure efficient management their health care.