A study of work patterns and self reported dust exposures of California farm operators was conducted. The study group consisted of 660 California farm operators selected from a group of 1,947 farm operators who had been surveyed 2 years (yr) previous about their farming operations and perceived exposures. They were interviewed by telephone questionnaire regarding their farming operations during the past 12 months (mo), how dusty they perceived them to be on a scale of 0 to 10, and how their farming work had changed over the past 10yr. A total of 114 subjects were eliminated from the study because they were no longer the primary farm operator or their farm sold less than 1,000 dollars in farm products the past year. The median age of the remaining 546 subjects was 54yr and 90.7% were male. They had spent a median of 15yr in fulltime farming operations. The median farm size was 65 acres. Most subjects (83%) reported being involved in crop related operations and 27% were involved in livestock related operations. Irrigation, supervision, and ground preparation were the three most frequently reported crop related activities. Mechanical harvesting and ground preparation were the dustiest operations with ratings of 5.4 and 4.6, respectively. Irrigation was considered the least dusty operation with a rating of 1.2. Checking animals, feeding hay, and animal handling were the three most frequently reported livestock related activities. Loading or cleaning of silos, feed storage, or pit storage were judged the dustiest operations; each received a dust rating of 4.3. Milking and cleaning equipment with disinfectants were judged to be the least dusty operations with ratings of 1.3 and 1, respectively. Approximately 52% of the farm operators reported using pesticides, with a median of 8 days of use over the past 12mo. The subjects reported that their dust, gas or fume, and pesticide exposures and proportion of time they spent in dusty operations had decreased over the past 10yr. The authors conclude that these data are a valuable source of information on exposures experienced by California farm operators.