The problem of morbidity in deployed military personnel represents a much-debated topic. Because there have been two cases of thyroid cancer in the Tuscania regiment, the aim of the present study was to investigate the prevalence of all types of thyroid disease in a cohort of carabineers. A total of 673 carabineers, including 501 deployed carbineers (DCs) (29-48 years of age) and 172 nondeployed carabineers (NDCs) (29-51 years of age), of the Tuscania regiment were involved in the study. Thyroid volume, percentages of single nodules and multinodular goiter, percentage of autoimmune thyroid disease, and percentages and histological types of thyroid cancer were all measured. No statistical difference between DCs and NDCs was found for any of the data. Furthermore, when we divided DCs into subgroups according to time spent on deployment and time elapsed since the first deployment, we found no differences. However, a high prevalence of thyroid cancer was found in our cohort (2.0% in DCs and 2.5% in NDCs; not significant), and the prevalence of thyroid cancer in nodules in the cohort of carabineers was higher (10.0%) than the prevalence of thyroid cancer in nodules in the civilian population (5.6%, p < 0.001). No differences regarding the prevalence of thyroid diseases were observed when we compared DCs and NDCs, which suggests that no significant difference in exposure to toxic or carcinogenic substances that could have affected the thyroid occurred during deployments. The high prevalence of thyroid cancer in carabineers may merely reflect an increase of this cancer in the general population, or it may suggest the presence of some carcinogenic event in this specific cohort.