Sexually transmitted infections (STIs) have always been a major health issue affecting military personnel in all types of services and in all armed forces around the world, especially during deployments and in operational settings. Although the research shows that STIs are still reported in the military, the epidemiological risk for contracting a sexually transmitted infection is much lower nowadays than it was in the past. It is important, however, that service members are routinely screened for sexually transmitted diseases. Because of a high prevalence of STIs in the general population as well as the asymptomatic nature of some infections (e.g. HIV, Chlamydia trachomatis), screening of the sexually active service personnel is recommended as a practical method of preventing the spread of STIs and their sequelae, such as pelvic inflammatory disease, ectopic pregnancy, infertility in women or epididymitis, prostatitis, infertility in men. The rates of STIs in service members have been on the increase in recent years, which may be associated with the fact that more and more women are now seeking a career in the armed forces. Currently, STIs do not only affect male soldiers or their civilian sexual partners (either long-term or casual), but both male and female soldiers alike, especially if they are serving together. The article focuses on the prevalence of STIs in the military in the past and at present, the common STI risk factors and prevention measures.