Primary fallopian tube carcinoma (PFTC) is a rare malignancy, but its incidence has been rising during the last decades and varies between 2.9/1,000,000 and 5.7/1,000,000. The epidemiology of PFTC has been sparsely studied. In Finland, the incidence rate has been rising during the last decades. The rise has been highest in the cities, in higher social classes, and in certain specific occupations. Parity gives protection against this disease, as does a previous sterilization procedure. Earlier thoughts of a previous salpingitis as a possible promoter of PFTC seem not to hold. Previous infections such as Chlamydia trachomatis infections or human papillomavirus infections cannot be regarded as risk factors. In this chapter, we clarify the possible epidemiological factors behind this disease.