Background: Puerperal sepsis is one of the major contributors to maternal mortality globally. Aim of the study: was to assess pregnant women's knowledge regarding puerperal sepsis and assess the effect of health instructions on pregnant women's knowledge. Research design: Quasi experimental (pre – posttest) research design was used. Sample: Were 100 pregnant women, (study group, control group) each group included 50 women. Setting: It was conducted at Antenatal Clinics at Sohag University Hospital, East Child Care and Al Shaheed Medical Center in Sohag City. Tools: structured interviewing questionnaire was used for data collection and health instructions booklet about puerperal sepsis. Results: It was observed that after applying the health instructions using booklet that there was a highly statistically significant difference between the pre and posttest in the study group regarding of total knowledge score of puerperal sepsis, 66% of women had good knowledge posttest in comparison with (20%) of women had good knowledge pretest, P-value is (0.001). Conclusion: Appropriate health education packages on puerperal sepsis during ANC, labor and delivery by health care providers to improve the knowledge of mothers. Recommendation: It is important to counsel mothers regarding puerperal sepsis and providing continuing educational program during antenatal and postnatal period regarding self-care practice to ensure best prevention of puerperal sepsis.