This study will look at how likely it is for HIV infection to be spread among partner types over time by recently HIV-infected men and their partners. The study will compare behaviors of recently HIV infected men to those with long-term HIV infection and no HIV infection. It will allow a study of sexual partnerships by actively recruiting sexual partners. We will also focus on the role of drug use, especially methamphetamine and how it changes behaviors over time. We will especially look at how different sex partners affects one's drug use and increases or decreases HIV transmission. The study will enroll 150 recently HIV-infected men who have sex with men and follow them for a year. In addition, up to 6 sexual partners of each recently HIV infected individual will be recruited and followed for a year. Some sexual partners will be HIV negative and some HIV positive. We will use their HIV status to compare behaviors over time in the group and between partners of the same status and partners of a different status. The results will be used in special formulas that will allow for a better understanding of behavior change by men with recent HIV infection. This new information will be key for designing new ways to target risk reduction for recently HIV-infected men.