A large part of the commercial flower production in Italy is located in the western part of the Liguria region, near the French border. The use of pesticides in this area has been much higher than the national average. The frequency of micronuclei in peripheral blood lymphocytes was evaluated in a group of 71 floriculturists working in this area and in a control group of 75 healthy blood donors living in the same area. A significant increase of micronucleated lymphocytes was observed in floriculturists as compared to unexposed subjects (8.57 vs. 6.67, p < .05). Females showed a marked increase in MN frequency (45% higher than males) independently of the exposure. A dose‐response relationship was observed between duration of exposure and MN frequency. The condition of exposure was also found to influence the micronuclei frequency. Increased relative risks in greenhouse workers (RR = 1.31) and in people working alternately in the greenhouse and in the open field (RR = 1.46) was observed with respect to the reference population.