While sunlight is critical in basal cell carcinoma (BCC) pathogenesis the relationship between exposure and tumor site and histology is unclear. We determined if tumor site (trunk or head/neck) or histology (nodular or superficial) is determined by exposure pattern. In 66 cases with truncal and 362 patients with head/neck BCC at first presentation, average hours exposure/year, intermittency score, childhood sunburning and skin type were not significantly associated with tumor site or histology. However, often sunbathing was associated with a five-fold increased risk of truncal BCC. Average sunbathing score was significantly greater in 22 cases with truncal compared with 325 cases with head/neck nodular tumors and also in 44 cases with superficial truncal compared with superficial head/neck BCC. Thus, sunbathing determined tumor site but not histology.