The Australian National Serosurveillance Program (ANSP) was established in 1997 to provide national estimates of population immunity to vaccine preventable diseases and inform immunisation policy in Australia. The 1st round tested opportunistically collected sera from pathology laboratories across Australia, a 2nd round was carried out in 2002, and a 3rd round of testing is currently ongoing using sera from 2007–08. This is the 1st systematic evaluation of the ANSP since its inception. Existing information and outputs from the ANSP were reviewed and used in conjunction with data collected from a survey of the program operators to evaluate the overall utility of the ANSP and the following system attributes; acceptability, stability, simplicity, flexibility, data quality, sensitivity, representativeness and timeliness. So far the ANSP has generated 26 peer-reviewed publications and provided useful data that have influenced and provided an evidence base for immunisation policy in Australia; for example informing mathematical models, which identified the need for the young adult measles-mumps-rubella immunisation campaign. However, difficulties have been encountered with obtaining enough samples for testing in the 3rd round currently being undertaken. This is a concern that has the potential to undermine the representativeness and stability of the system, and other methods of sample collection must be investigated. Serological surveillance is an important component of any comprehensive system for monitoring population immunity to vaccine preventable diseases and evaluating the effectiveness of immunisation programs. However, an effective ongoing program requires strong support to ensure it remains sustainable in an era when laboratory based population health research for the public good is becoming increasingly challenging. Commun Dis Intell 2010;34(1):29–36.