Data were collected from 1169 gay circuit party patrons in three North American circuit parties in three geographical locations in 1999. Questionnaires obtained reasons for attending circuit parties and drugs used at circuit parties. Factor analyses of the 10 major reasons for attending parties indicated that there were two significant moderately correlated dimensions: a social and celebratory one to be with friends and dance, and a sensation-seeking one, to have sex and drugs. Drug and sex on drugs predictors of the social dimension accounted for only 3.8% of its variance and included alcohol, ecstasy (methylenedioxymethamphetamine), GHB (γ-hydroxybutyrate), and having sex while on alcohol as significant predictors. Drug predictors for the sensation-seeking dimension accounted for four times the variance of the first dimension and included poppers, alcohol, ecstasy, Special K, and GHB, and having sex while on methamphetamines and on GHB. Unsafe sex was significantly associated with the sensation-seeking dimension but not the social dimension. While 63% checked ≥3 of the social reasons for attendance, only 13% checked ≥3 of the sensation-seeking reasons for attendance. Age was significantly inversely associated with the social dimension. These data suggest that while drug use is significantly associated with both the sensation-seeking and social dimensions of circuit party attendance, a greater number of drugs, sexual activity while on drugs, and unsafe sex are more closely associated with the sensation-seeking dimension of attendance.