Hepatitis A and hepatitis B are 2 common sexually transmitted diseases that are preventable by vaccination. Men who have sex with men (MSM) are at increased risk of acquiring hepatitis A virus and hepatitis B virus through sexual exposure. Current guidelines from the Centers for Disease Control and Prevention recommend that MSM receive immunizations against hepatitis A and hepatitis B. Many health care providers and most MSM are unaware of the risks and the potentially dangerous consequences posed by hepatitis A and B virus infection, and the MSM thus remain unvaccinated and unprotected from exposure to these viruses. It is important for health care providers to educate and vaccinate their at-risk male patients against hepatitis A and hepatitis B virus infections.