Background: Hyperemesis gravidarum (HG) is characterized by persistent nausea and vomiting accompanied by ketosis and loss of weight. The Helicobacter pylori (H. pylori) are considered as an important cause of gastritis in human beings and as an essential factor in the pathogenesis of peptic ulcer. This study aimed to investigate the association of Helicobacter Pylori infection in pregnant women with Emesis and Hyperemesis Gravidarum.. Methods: This comparative cross sectional study included 90 pregnant women in the Obstetrics and Gynecology Department of Benha University Hospitals & Health Insurance Hospital. Patients were divided into three groups. Group A: included 30 pregnant women complicated with HG, Group B: included 30 pregnant women complicated with emesis gravidarum and Group c: included 30 healthy pregnant women having neither emesis nor hyperemesis gravidarum of matched age as control group. All studied cases were subjected to general examination, complete physical and cardiac, abdominal examination, trans-abdominal or Transvaginal pelvic ultrasound and routine laboratory investigations. Results: The incidence of H. pylori was significantly higher in group A and B compared to group C (P=0.016). IgG antibody titer was significantly higher among group A and B compared to group C (P=0.001). Conclusion Our results suggest that there was a strong association between H pylori and hyperemesis gravidarum, allowing us to conclude that when a pregnant patient is complaining of hyperemesis gravidarum, we should do a test for H pylori seropositivity.