Among the minorities underserved by today's healthcare system, the lesbian, gay and bisexual (LGB) population may be the least studied, and the least understood by healthcare providers. High-quality evidence is often lacking regarding optimal preventive care measures, both in medical areas that (to date) fail to identify differences in need between LGB and heterosexual patients, and in those more prevalent in or more specific (or both) to sexual minorities. Issues of substance abuse, sexual health and sexually transmitted diseases, obesity and other eating disorders, cardiovascular prevention, cancer prevention and screening, depression and other psychological disorders, social isolation and personal and intimate partner violence are all as or more important to address in LGB patients as they are in the general American population. Although many barriers to the delivery of quality healthcare to these patients exist, support from governmental, professional and private organizations can assist both patients and providers in overcoming these barriers.