Purpose: The purpose of this study was to determine the effects of Nei-Guan(P6) acupressure on nausea and vomiting in pregnant women having hyperemesis gravidarum. Method: The research design was a randomized control-group pretest-posttest repeated measure design with counter balancing. For the experimental treatment, P6 acupressure was carried out for ten minutes. Data was collected from April 1. 2003 to April 30. 2004. The participants were 66 patients admitted with hyperemesis gravidarum. They were divided into three groups, a P6 acupressure group, placebo point group and a control group. Result: Hyperemesis gravidarum patients who received P6 acupressure during admission experienced much less nausea and vomiting than the placebo acupressure and control group(F=8.259, p=.001). Conclusion: Nei-Guan(P6) acupressure is considered an effective intervention for reducing nausea and vomiting in pregnant women having hyperemesis gravidarum. Further more Nei-Guan(P6) acupressure maybe used as an independent nursing intervention method for pregnant women with severe nausea and vomiting.