Breastfeeding is nurturing, cost-effective, and beneficial for the health of mother and child. Babies receiving formula are sick more often and are at higher risk for childhood obesity, diabetes, asthma, and other conditions compared with breastfed children. National and international organizations recommend exclusive breastfeeding for 6 months. Exclusive breastfeeding in Asian and Native Hawaiian or Other Pacific Islander (NHOPI) subgroups is not well characterized. Data from the 2004–2008 Hawaii Pregnancy Risk Assessment Monitoring System, a population-based surveillance system on maternal behaviors and experiences before, during, and after pregnancy, were analyzed for 8,508 mothers with a recent live birth. We examined exclusive breastfeeding status for at least 8 weeks. We calculated prevalence risk ratios across maternal race groups accounting for maternal and sociodemographic characteristics. The overall estimate of exclusive breastfeeding for at least 8 weeks was 36.3 %. After adjusting for maternal age, pre-pregnancy weight, cesarean delivery, return to work/school, and self-reported postpartum depressive symptoms, the racial differences in prevalence ratios for exclusive breastfeeding for each ethnic group compared to Whites were: Samoan (aPR = 0.54; 95 % CI 0.43–0.69), Filipino (aPR = 0.58; 95 % CI 0.53–0.63), Japanese (aPR = 0.58; 95 % CI 0.52–0.65), Chinese (aPR = 0.64; 95 % CI 0.58–0.70), Native Hawaiian (aPR = 0.67; 95 % CI 0.61–0.72), Korean (aPR = 0.72; 95 % CI 0.64–0.82), and Black (aPR = 0.79; 95 % CI 0.65–0.96) compared to white mothers. Providers and community groups should be aware that just over one-third of mothers breastfeed exclusively at least 8 weeks with lower rates among Asian, NHOPI, and Black mothers. Culturally appropriate efforts to promote exclusive breastfeeding are recommended particularly among Asian subgroups that have high breastfeeding initiation rates that do not translate into high exclusivity rates.