Objectives: To investigate trends in notification rates of Chlamydia trachomatis in Tasmania Australia, by population sub-groups, from 1 January 2001 to 31 December 2007 Methods: An enhanced surveillance dataset was used to supplement case notifications Rates based on age group were analysed by sex, geographic region, indigenous status, sexual exposure, reason for testing and healthcare provider Results: In all age groups, the notification rate increased steeply The highest rates were seen in the ages 15-24 years, this age group represented 15% of the population but accounted for 74% of the chlamydial notifications The increased rates in females aged 15-24 years and males 15-19 years in Tasmania were larger than the increases observed nationally Rates were consistently higher in urban areas Females were more likely to have been tested as a result of screening, and males were more likely to have been tested when presenting with symptoms or as a result of contact tracing The majority of cases reported sexual exposure with opposite sex partners only Conclusions:This study highlights the increasing significance of chlamydial infection as a public health issue, the gender differences in health-seeking behaviour, and the discrepancies in testing patterns These findings will assist with the design of health promotion programs