This study was performed to examine the cancer risk of Danish gardeners having been highly exposed to pesticides. We have followed a cohort of 4,015 employed gardeners (859 females and 3,156 males) from May 1975 until the end of 1984 with regard to cancer incidence. The observed incidence was compared with expected numbers calculated from national incidence rates. For all cancer sites combined, the standardized morbidity ratio (SMbR) was 104. Among male gardeners a significantly increased incidence was seen for soft tissue sarcoma (SMbR = 526, 95% confidence interval (CI): 109-1,538), and chronic lymphatic leukemia (SMbR = 275, 95% CI: 101-599). The incidence of non-Hodgkin's lymphoma was twice that which was expected (SMbR = 200, 95% CI: 86-393). We suggest that some of the pesticides to which the gardeners have been exposed are capable of initiating or promoting the development of malignant neoplasms in tissues of mesenchymal origin. © 1992 Wiley-Liss, Inc.