The operational tempo of the Australian Defence Force has increased over the last two decades. We examine the relationship between health of personnel and the frequency and duration of their deployment. Self-reported health measures (number of symptoms, Kessler Psychological Distress Scale, and Post Traumatic Stress Disorder Checklist) were compared for people who had never deployed to those who had deployed only once and for those who had deployed at least twice with at least one deployment to East Timor and one deployment to Afghanistan or Iraq. Comparisons were also made between people who had deployed for at least one month and those who had deployed for longer periods. Frequency of deployment but not duration of deployment was associated with poorer health.