Background: Pregnancy is a special stage linked to various biopsychosocial changes. Several unhealthy lifestyle behaviors may occur during pregnancy that may have potential substantial impacts. Aim: To assess health risk behaviors among pregnant women 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 in the three selected maternal and child health centers. Tools: Three tools were used: Tool 1: Structured interview questionnaire which include data about (sociodemographic characteristics, obstetric history, history of chronic diseases and current complain). Tool 2: Include two parts which used to assess mother's knowledge and reported practice regarding health risk behaviors during pregnancy. Tool 3: Women's attitude regarding health risk behaviors during pregnancy. Results: Illustrated that (65.8%) of pregnant women had poor score of knowledge, (64.1%) good reported practice and (51.1%) of them had positive attitude about health risk behaviors during pregnancy. Regarding sociodemographic characteristics, there was a statistically significant difference between knowledge, reported practice and attitude where p= 0.000*. Conclusion: About two third of studied pregnant women had fair score of reported practice and poor score of knowledge while about half of them had positive attitude. Recommendation: Health education program is needed to increase awareness of pregnant women about healthy behaviors during pregnancy.