Lymphoma, multiple myeloma and leukaemia mortality among French male farmers and farm laborers (1984-1986) has been studied geographically. In each geographical area (89 "départements") exposure to pesticides in arable land has been characterized by an index taking into account different practices in the treatment of various crops as well as an estimate of the time per farmer spent cultivating each crop in 1970. The farmers population as a whole presented an increased mortality for multiple myeloma (SMR = 1.59, 95% CI = 1.32-1.89) and leukaemia (SMR = 1.33, 95% CI = 1.19-1.49) but not for lymphoma (SMR = 1.09, 95%, CI = 0.94-1.26). Using Poisson regression, leukaemia mortality appeared significantly linked to the pesticide exposure index (P = 0.04), after adjustment of farmers' economic status and a linear geographical gradient, whereas no significant relationship was found for lymphoma or multiple myeloma. This result reinforces a similar link reported from a previous French geographical study conducted at a smaller scale within a region.