Recruitment of young people for epidemiologic research remains challenging, with marked decreases in the effectiveness of face-to-face, mail, and telephone recruitment methods. We report on the implementation and feasibility of an innovative and flexible approach used to recruit participants for a longitudinal cohort study about contraceptive use and pregnancy (the Contraceptive Use, Pregnancy Intention, and Decisions (CUPID) Study). Australian women aged 18-23 years were recruited using a range of online, networking, and offline methods, including social media (primarily Facebook (Facebook Inc., Menlo Park, California; http://www.facebook.com)), face-to-face events, distribution of promotional material, and media releases. Over the course of the 1-year recruitment period (beginning in September 2012), a total of 3,795 eligible women were recruited to complete the online survey, at a cost of approximately A$11 per participant. This sample was found to be broadly representative of the Australian population of women aged 18-23 years in terms of demographic characteristics, with the exception of an overrepresentation of tertiary-educated women (88.7% compared with 72.6%). This study demonstrated that although current recruitment strategies are required to be innovative and flexible in order to engage young people in epidemiologic research, representative samples can be achieved online at reasonable cost.