Background: The health and progress of any society largely depends on the health of its women. Pregnancy changes women's lifestyle and they should at least begin to lead a healthy lifestyle and perform health promoting behaviors during this critical period of reproductive age in order to avoid problems that could harms themselves or their families. Aim: To assess the pregnant women's knowledge and practice about health behaviors during pregnancy at Sohag city. Subjects and Method: A descriptive cross- sectional research design was used in the study by using systematic random sample technique, 354 pregnant women had been chosen from three selected maternal and child health centers at Sohag city. Tools: two tools were used: Tool I: Include three parts: part one: Socio demographic characteristics, Part two: Obstetric history of pregnant women and Part three: Pregnant women's Knowledge about the health behaviors during pregnancy. Tool II:  Health practice questionnaire used to assess Pregnant women's reported practice regarding health behaviors during pregnancy. Results:  There was positive correlation between knowledge and practice scores with (r= 0.307 and p=0.000*) and there was statistically significant difference between reported practice with occupation education & social class (p<0.05). Conclusion: The studied pregnant women had poor level of knowledge and fair score of reported practice about the health behaviors during pregnancy. Recommendation: Health education program is needed to increase knowledge of pregnant women about healthy behaviors during pregnancy.