Insight on how different missions have impacted rates of mental health service (MHS) utilization is unexplored. We compared postdeployment MHS utilization in a national cohort of first-time deployed to missions in Balkan, Iraq, and Afghanistan respectively. A prospective national cohort study of 13 246 first-time deployed in the period 1996 through 2012 to missions in Balkan area, Iraq, or Afghanistan respectively. Soldiers 'MHS utilization was also compared with a 5:1 sex-, age-, and calendar year-matched never-deployed background population. Postdeployment utilization of MHS was retrieved from national coverage registers. Using Cox survival analyses, participants were followed and compared with regard to receiving three different types of psychiatric services: (i) admission to psychiatric hospital, (ii) psychiatric outpatient contact, and (iii) prescriptions of psychotropics. Utilizing of psychiatric outpatient services and psychotropics was significantly higher in first-time deployed to Iraq and Afghanistan compared with deployed to Balkan. However, the rate of postdeployment admission to psychiatric hospital did not differ between missions. Postdeployment rates of psychiatric admission and psychiatric outpatient treatment were significantly higher in Afghanistan-deployed personnel compared with the background population. Utilization of MHS differed significantly between mission areas and was highest after the latest mission to Afghanistan.