Hispanic migrant agricultural workers' exposure to pesticides and other agrichemicals places them at increased risk for a variety of acute and chronic conditions, including cancer. As a socioeconomically disadvantaged group, migrant workers also face many barriers to effective cancer control. In 1992, a series of focus groups was held with 55 Hispanic migrant agricultural workers (22 women, 33 men) in central Wisconsin to gather information on their knowledge and attitudes regarding cancer etiology and treatment, their practices regarding cancer screening and early detection, and their concerns regarding occupational exposure to pesticides. Beliefs that pesticides are toxic and can cause health problems were common among participants. In addition, however, participants reported that they are reluctant to demand occupational protections to which they are entitled because they are afraid of losing their jobs. Study results also suggest that barriers to effective primary and secondary prevention of cancer in this Hispanic migrant agricultural worker population include knowledge and information barriers, cultural barriers, and socioeconomic barriers. A lack of knowledge and information regarding the causes of cancer, its prevention, and its early detection and treatment was evident among participants, which in turn was reflected in strong fatalistic attitudes toward the disease. Cultural barriers included attitudes of embarrassment and shame associated with physical examinations and women's strong discomfort with male clinicians. Socioeconomic barriers to secondary prevention included the cost of obtaining health services, time constraints associated with the need to work and long working days, and a lack of transportation. Efforts to improve cancer screening as well as other preventive health services in the Hispanic migrant agricultural worker population must acknowledge these barriers and address as many of them as possible to be successful.