An excessive incidence of non-Hodgkin's lymphoma (NHL) has been reported among farmers and other occupational groups working with pesticides. Some pesticides exhibit immunotoxic and genotoxic activities. Individuals exposed to pesticides have also been found to have an increased prevalence of chromosomal abnormalities including the t(14;18)(q32;q21), one of the most common chromosomal abnormalities in NHL. Two recent epidemiologic studies reported that the association between pesticide exposures and risk of NHL was largely limited to NHL cases with the chromosomal translocation t(14;18). This review summarizes the findings from these epidemiologic studies, speculates on implications, and suggests the research needed to clarify the role of pesticides in NHL.