Significant gaps remain between recommendations of evidence-based guidelines and primary health care practice in Australia. This paper aims to evaluate factors associated with the use of guidelines reported by Australian GPs. Secondary analysis was performed on a survey of primary care practitioners which was conducted by the Commonwealth Fund in 2009: 1016 general practitioners responded in Australia (response rate 52%). Two-thirds of Australian GPs reported that they routinely used evidence-based treatment guidelines for the management of four conditions: diabetes, depression, asthma or chronic obstructive pulmonary disease and hypertension - a higher proportion than in most other countries. Having non-medical staff educating patients about self-management, and a system of GP reminders to provide patients with test results or guideline-based intervention or screening tests, were associated with a higher probability of guidelines use. Older GP age was associated with lower probability of guideline usage. The negative association with age of the doctor may reflect a tendency to rely on experience rather than evidence-based guidelines. The association with greater use of reminders and self-management is consistent with the chronic illness model.