Recreational use of marijuana is relatively common in the United States, and medicinal use is gaining popular and legal support. Marijuana has been proposed as a potential treatment for hyperemesis gravidarum. Research into this topic is complicated by associations between marijuana use and poor birth outcomes. Cannabinoid hyperemesis syndrome, which can cause severe nausea and vomiting in marijuana users, is another complicating factor. Hawai‘i Pregnancy Risk Assessment Monitoring System data from 4,735 respondents were used to estimate prevalence of self-reported marijuana use during and in the month before pregnancy, as well as severe nausea during pregnancy. Data were weighted to be representative of all pregnancies resulting in live births in Hawai‘i between 2009 and 2011. Prevalence ratios (PR) and 95% confidence intervals (CI) were computed to estimate associations. Of recently-pregnant women in Hawai‘i, 6.0% reported using marijuana in the month before pregnancy, and 2.6% reported using marijuana during pregnancy. Approximately 21.2% reported severe nausea during pregnancy. Women who reported severe nausea during pregnancy were significantly more likely to report marijuana use during pregnancy (3.7% vs 2.3%; PR=1.63, 95% CI: 1.08-2.44). More research is needed to investigate the relationship between marijuana use and severe nausea during pregnancy, and to quantify associated risks to mother and fetus.