Abstract: The practice of paying research participants has received significant attention in the bioethics literature, but the focus has been almost exclusively on consideration of factors relevant to determining acceptable payment amounts. Surprisingly little attention has been paid to what happens once the payment amount is set. What are the ethical parameters around how offers of payment may be advertised to prospective participants? This article seeks to answer this question, focusing on the ethical and practical issues associated with disclosing information about payment, and payment amounts in particular, in recruitment materials. We argue that it is permissible—and indeed typically ethically desirable—for recruitment materials to disclose the amount that participants will be paid. Further, we seek to clarify the regulatory guidance on “emphasizing” payment in a way that can facilitate design and review of recruitment materials.