This data briefing summarises the main findings from the 2004-05 Alcohol and Other Drug Treatment Services (AODTS) NMDS data for WA. Throughout this briefing, data from WA are presented along with 2004-05 national AODTS-NMDS data. Highlights include: 40 government-funded alcohol and other drug treatment agencies provided 16,092 'closed treatment episodes'; one-third (33%) of closed treatment episodes were for clients aged 20-29 years and more than one-quarter (27%) were for clients aged 30-39 years; and male clients accounted for 62% of all closed treatment episodes.