Changes in age-standardized cancer registration rates in the Swiss Canton of Vaud (population 530,000) over the two five-year calendar periods 1978-82 and 1983-87 were analyzed. The incidence of occurrence at lung and other tobacco-related sites remained stable (or slightly decreased in males), but showed a substantial increase in females (approximately 40%, from 6.8 to 9.5/100,000 world standard, for lung alone). Other upward trends were observed for skin in both sexes (approaching 50% for melanoma in males), female breast (+8.0%, reaching 69.5/100,000), ovary and urinary tract neoplasms. In contrast, declines were observed not only for stomach and cervix, but also for intestine, gallbladder and endometrium. Consequently, overall total cancer incidence (excluding non-melanomatous skin) declined by 1.1% in males, but increased by 2.7% in females, reaching values of 277.9 and 205.4/100,000, respectively, in 1983-87. The absence of any substantive trends in incidence for cancers of the prostate, testis, brain and multiple myeloma is of potential interest, and represents an important indicator of the uniformly high standard of monitoring by this cancer registration scheme. In a public health perspective, it is discouraging that most of the increases were restricted to cancer sites whose etiology has long been well defined, i.e., tobacco for females and sunshine or other sources of non-ionising radiation, although it is reassuring to be able to document the levelling of tobacco-related cancer incidence in males.