Background: Oral contraceptives (OCs) are the most widely used contraceptive method among women of reproductive age in the United States (US). Routine download and use of health-related smartphone applications (apps) continues to increase. Objective: The purpose of this study was to evaluate the utility of English-language, smartphone-platform OC reminder apps currently available for download in the US. Methods: During June-July 2013, official Internet-based, mobile app platforms for the two major smartphone operating systems in the USdAndroid (Google Play Store) and iPhone (iTunes) dwere searched. "Birth control," "the pill," and "contraception" were entered into the search-bar of each Smartphone store. Apps were assessed for the following: cost, health care professionals' involvement in app development, reminder mechanisms, and functionality. Results: Of the 39 unique OC reminder apps meeting inclusion criteria, 7 (18%) did not operate as intended when downloaded. Most apps functioned without an Internet connection (97%) and included pop-up notifications (84%). Conclusions: Certain app features overcome common causes of missing an alarm, and hypothetically, may minimize likelihood of an OC user missing a daily pill. Health care providers should inform users of potential pitfalls and advise them that an OC reminder app should be not be used as a sole reminder method. (C) 2015 Elsevier Inc. All rights reserved.