A case-control study was conducted in a rural area of Achaia in western Greece to examine the risk factors of brucellosis. The participants in the study were 414 (7.5% of the whole population of the investigated municipality). The cases (n = 140) were defined by clinical symptoms and confirmed by a positive standard agglutination test (SAT). All cases have been diagnosed between January 1997 and March 1999 either by physicians of the Local Health Center or by private practitioners. Two criteria were basic to establish the disease. The first one was clinical symptoms such as fever, fatigue, arthralgia and generalized aches and the second was a titer of SAT at least 1:160. Controls (n = 274) were matched with cases for age and gender in a 1:2 ratio. Approximately collection of controls was performed among those presented to the local Health Center for other diseases. Data were collected by the same physician via a personal interview and analyzed by logistic regression models. The overall incidence of the disease in the region was found to be 1110/100,000. Taking 'no ownership of animals' and 'no contact of animals' as the reference category, the strongest risk factor was trauma during animal delivery with an odds ratio (OR): 24.3; 95% confidence interval (CI): 8.8-67.5 following by absence of stables (OR: 14.4; 95% CI: 4.7-44.1). After application of multivariate stepwise analysis the adjusted risk factors remaining in the model were the place of residence (OR: 1.8; 95% CI: 1.1-3.1), professional occupation with animals (OR: 2.4; 95% CI: 1.2-4.8), absence of stables (OR: 9.1; 95% CI: 2.2-38.7) and trauma during animal delivery (OR: 11.2; 95% CI: 3.2-39.1). Consumption of cheese from pasteurized milk or consumption of cheese matured for over 3 months was found to be a protective factor (OR: 0.27; 95% CI: 0.11-0.67). The detection of brucellosis in animals is essential for the prevention of the disease. In addition efficient preventive measures should be established in order to eliminate the disease.