The roles of farm practices, occupational exposures to organic solvents, and ionizing radiation in the risk of hairy cell leukaemia (HCL) were examined in a French hospital-based multicentre case-control study including 291 cases (229 men and 62 women) and 541 controls (425 men and 116 women). No positive association was observed with occupations involving exposure to organic solvents or with self-declared exposures to solvents, but a significant association with self-reported exposure to petrol or diesel was found for men (OR = 1.5 CI95% [1.0-2.1]). No association with ionizing radiation was detected. Agriculture employment gave an odds ratio of 1.7 (CI95% [1.1-2.4]) for men and 2.7 (CI95% [1.1-6.7]) for women. Among men, the association seems to affect farmers rather than agricultural workers. Self-declared exposure to pesticides or bovine cattle breeding was related to HCL risk in both genders. Finally, a significant negative association with smoking was observed in men, with an inverse exposure-risk relationship odds ratios of 0.6, 0.5 and 0.2, respectively, for cumulative consumptions of < 10, 10-23 and > or = 24 pack-years), contrasting with an odds ratios clearly > 1 in women.