Objective: To determine same day pharmacy availability of ulipristal acetate, evaluate for differences in availability expressed to patients and physicians, and to compare the availability of ulipristal acetate with that of levonorgesterel-containing emergency contraceptive pills. Methods: We conducted an observational population-based study utilizing a telephone-based secret shopper methodology. Researchers called all 195 unique retail pharmacies in the state of Hawaii, posing as patients and physicians. Results: Only 2.6% of pharmacies had ulipristal acetate currently available, with an additional 22.8% reporting the ability to order the medication. In contrast, 82.4% reported immediate availability of levonorgesterl emergency contraceptive pills. There was no significant difference in availability reported to patient and physician callers. Conclusions: Despite its higher efficacy, availability of ulipristal acetate is limited and significantly lower than that of levonorgestrel products. Even with a prescription, women face significant barriers to obtaining ulipristal acetate, the most efficacious dedicated emergency contraceptive pill available in the US systems-based interventions are needed to address such barriers.