This study examines motives for and consequences of MDMA use at different types of dance parties in the Netherlands (2001 and 2002). Participants were 490 visitors of three different types of rave parties, "club/mellow," "trance/mainstream," and "hardcore" (34% female, mean age 22.3 years, 76.5% MDMA users). Partygoers are motivated primarily by the energetic and euphoric effects they expect from MDMA. Quantity of MDMA use is associated with hardcore and trance/mainstream party style, with the motives of euphoria, sexiness, self-insight, and sociability/flirtatiousness (negative), and with gender, educational level (negative), and MDMA use by friends. Women report more (acute) negative effects--depression, confusion, loss of control, suspiciousness, edginess, nausea, dizziness--than men; and in particular, women who are motivated to cope with their problems by using MDMA are at risk. Men's polydrug use and notably their motivation to conform to friends by using MDMA are associated with negative effects.