: This five year study entitled """"""""Club Drugs, Resource Inequities and Health Risks among Urban Youth"""""""" will identify the contextual, socio-cultural and psychological factors that influence urban youth and young adults to incorporate club drugs into their drug repertoires, changes in drug use patterns over time, and the psychosocial, economic and health consequences of club drug use and concurrent polydrug mixing. The study responds to NIDA's RFA DA-0 1 -0 10 entitled """"""""Responding to Club Drugs And Other Emerging And Current Drug Abuse Trends."""""""" Study aims are to: 1) describe the marketing and diffusion of club and designer drugs into urban youth and young adult drug markets through clubs, after-hours, and other social activities, and describe the meaning of these drugs in relation to traditional street drugs (regular and high THC marijuana, leaves with formaldehyde, alcohol, dust, cocaine, crack and heroin), 2) conduct a panel study with two time points eight months apart with 500 youth ages 16 - 30 to deter-mine changes in patterns of MDMA and other dance and prescription drugs, and predictors and consequences of use, 3) utilize the information to develop strategies for dance and prescription drug risk prevention in street and party settings. Component 1 (Months I - 50) of the study will continue established patterns of ethnographic research in settings where urban youth and young adults buy, sell, learn about and experiment with new drugs and drug mixing. Component 2 (Months 8 - 58) will involve administering an epidemiologic/network survey to the study cohort of 500 youth and young adults between the ages of 16 - 30. In Component 3 (Months 42-60) we will use ongoing study results in partnership with a team of youth consultants to develop and pilot test for acceptability a strategy for preventing risks associated with MDMA and other club drug use and drug mixing to be utilized in drug use sites, with distributors and in networks of users. Throughout, we will review and integrate emerging literature linking findings to the primary theoretical concepts guiding the study. The significance of the study lies in its description of the ways in which new potentially dangerous drugs are diffused into a high risk urban environment, its incorporation of the psychosocial, economic and contextual factors in understanding drug selling, its focus on understudied polydrug use among urban youth, its examination of neighborhood factors in drug selection and use, and its partnership with youth and youth-serving clubs and site gatekeepers to engage in risk reduction. The study promises to produce new analytic and theoretical insights into the diffusion of new drugs into already saturated urban youth drug markets and the consequences of their use.