This protocol seeks to better understand the various factors which influence an HIV infected individual's decision to participate in clinical research, and especially how the offer of payment influences the decision to participate and understanding of the risks, benefits and purpose of the research. Subjects will be HIV infected individuals participating in or being screened for participation in intramural HIV studies being conducted by the NIAID, CCMD, and NCI. Willing subjects will be recruited from studies that offer payment and comparable studies that do not pay. The primary methodology is an interview via a survey schedule. Use of the interview schedule will be preceded by a focus group of about 7-10 individuals and pretesting of the survey instrument. Paid and unpaid subjects will be compared with respect to motivations, understanding, willingness to withdraw, and sociodemographics.