Purpose: The aim of this study was to assess health-related behavior of pregnant women and breastfeeding mothers by investigating relevant risk factors. Methods: Data of 10,396 women (age 19 to 49 years) from the Korea National Health and Nutrition Examination Survey report from 2007 to 2012 was used to analyze factors associated with health-related behavior. The subjects were divided into pregnant women; breastfeeding mothers; and non-pregnant women. Bottle feeding mothers were excluded. Results: Current smoking rate including self-reported smoker and/or positive cotinine urine test were lower for pregnant or breast-feeding group than non-pregnant group. Heavy-drinking was not different among groups while monthly drinking rate was higher in non-pregnant group. Rate of stress recognition was lower in pregnant and breast-feeding group than non-pregnant group. Rate of experience for depressive symptoms and rate of suicidal ideation were not different among groups. Conclusion: Pregnant women and breast-feeding mothers maintain a good pattern of health- related behavior compared to non-pregnant women. However, substantial proportion of pregnant women and breast-feeding mothers continue to drink and smoke. This shows the need for a plan that will modify health-related behavior.