Trends in incidence and survival from soft tissue sarcomas (STS) were analysed for the period 1974-1994 using data from the Cancer Registry of the Swiss canton of Vaud. A total of 645 cases were registered. The most common histotypes were fibrosarcoma (0.82/100,000 males, 0.86/100,000 females, world standard, 1990-1994), leiomyosarcoma (0.90/100,000 males, 1.28/100,000 females, 1990-1994), and Kaposi's sarcoma (3.10/100,000 males in 1990-1994). Overall incidence rates for STS increased from 2.68/100,000 males in 1974-1979 to 6.86 in 1990-1994, and from 3.61 to 4.27 in females. However, after excluding Kaposi's sarcoma, no consistent trend over time was observed, peak rates (approximately 4.40/100,000) being registered in the late 1980s for both sexes, with some levelling off thereafter. Five-year relative survival was 17% for Kaposi's sarcomas, and 51% for other STS (all STSs, 45%). These data indicate that there has been no major new risk factor for STS of such a relevance to modify appreciably the overall rates on a population level, except from the impact of the AIDS epidemic for Kaposi's sarcoma.