OBJECTIVE:To measure chlamydia testing and positivity rates among 16-39 year olds attending Aboriginal Community Controlled Health Services (ACCHSs). METHODS:Retrospective non-identifiable computerised records containing consultation and chlamydia testing data were collected for patients (16-39 years) attending eight ACCHSs during 2008-09 in urban, regional and remote settings for the Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) system. Annual chlamydia testing and positivity rates were estimated. RESULTS:Over two years, 13,809 patients aged 16-39 years (57.8% female, 82.3% Aboriginal or Torres Strait Islander) attended. The annual overall chlamydia testing rate was 13.0% (2008) and 16.0% (2009). Testing rates were higher among females (p<0.001) and among patients aged 16-29 than 30-39 years (males: p=0.01; females: p<0.001). Chlamydia positivity was 8.5% overall; similar in females (8.7%) and males (7.8%) (p=0.46); highest among 16-19 years (females: 17.4%; males: 13.0%), declining to 1.5% among females 35-39 years (p<0.001) and 4.8% among males 30-34 years (p<0.001). CONCLUSIONS:Chlamydia testing at these ACCHSs approached recommended levels among some patient groups, however, it should increase. High positivity among younger people highlights they should be targeted. IMPLICATIONS:Young people should be targeted for sexual health interventions. ACCHSs are well placed to provide enhanced sexual health services if appropriately resourced.