We created this publication because sexual health issues affecting bisexuals have been largely ignored and under-represented in discussions of heterosexual and/or lesbian, gay and transgender health. Bisexual men and women are expected to have the same health concerns as either heterosexuals or gay men and lesbians, and therefore their unique concerns are seldom addressed. This publication is designed to meet the needs of many populations. For journalists, researchers, counselors and anyone seeking to better understand bisexuality and HIV/STI prevention, we describe bisexuality and HIV/STI transmission, and offer language for understanding and explaining these trends clearly and accurately. For staff of HIV/STI prevention programs, bisexual activists, public health departments and funders we detail existing programs’ challenges and offer solutions.