A study of 49 randomly selected, full-time dairy farmers was performed to assess the prevalence and nature of hearing loss in this population. An age- and sex-matched group of rural, non-farmers was also studied. Medical, occupational, and recreational histories were taken and standard audiometric testing was administered. Sixty-five percent of farmers had hearing loss in the higher frequencies and 37% had losses in the mid-frequency range as compared to 37% and 12% of non-farmers respectively (p less than .01). Farmers' left ears were more severely affected. The age of the subjects and the number of years spent farming were highly correlated with hearing loss. Correlation and regression analyses supported the hypothesis that the difference in the prevalence of hearing loss between the dairy farmers and the non-farmers was due to occupational noise exposure on the farm.