Sinonasal cancer, the cancer of the nose and paranasal cavities, is rare with an incidence below 2/100,000 person-year; the incidence is lowest among women and with distinct differences between countries. These variations in incidence are mostly explained by differences in occupational exposure, in particular exposure to wood dust, which is by far the major risk factor. This chapter gives an overview of epidemiological studies on sinonasal cancer dealing with epidemiological evidence for various occupational risk factors, exposure characteristics, tumor pathology, findings from experimental and human studies contributing to understanding of cancer mechanisms, and, finally, with molecular alterations observed in sinonasal cancer tissue available as potential molecular markers. The main studies and their findings as well as the principal pathological features of sinonasal tumors are summarized in tables and exemplified in illustrations.