Background: Hyperemesis gravidarum is the severe form of nausea and vomiting of pregnancy. The reported incidence of Hyperemesis gravidarum is about 0.5-2.0%. For the diagnosis of hyperemesis gravidarum there must be presence of three or more vomiting episodes during the day, weight loss of over 5% and ketonuria. Studies have recently suggested that there is an association between emesis gravidarum and hyperemesis gravidarum with Helicobacter pylori infection. Serologically positive H. pylori infection has been demonstrated in hyperemesis patients. Objective: To detect if there is association between hyperemesis gravidarum and infection with helicobacter pylori. Methods: The study included 200 women that were classified into two groups. Group (1) 100 women with hyperemesis gravidarum and group (2) 100 women with usual antenatal care. Serum H. pylori titre was measured for detection of seropositivity incidence in both groups. Results: Regarding H. pylori IgG titre, there was significant difference between study group and control group. Conclusion: This study concluded that there is significant correlation between Helicobacter pylori infection and occurrence of emesis gravidarum.