A case-control study was used to determine whether cases of farm injury were more likely than controls to have been regularly exposed to certain types of medication including those that cause side effects which may predispose to injury. Persons reporting an injury (n = 176) were identified in a population-based mail survey of people on 1364 Ontario farms, and compared to people without injuries using a 4:1 control: case ratio. Bivariate, stratified, and multivariable analyses were used to quantify the strength of associations between exposures to certain medications and the occurrence of farm injury. Those who regularly used certain types of medication were separated into two groups: people who used the medications in isolation, and those who used the medications in combination with other medications. Response to the survey was 77.3% among cases and 82.6% among controls. Strong and statistically significant increases in risk for injury were observed in association with the regular use of stomach remedies or laxatives by males (OR 2.8; 95% CI: 1.0,7.7), and regular use of heart of circulatory medications by men over the age of 45 (OR 4.2; 95% CI: 1.2,14.7). The identified associations remained after adjustment for age, co-morbidity, tillable farm acreage, education, income, alcohol consumption and tobacco use. Several possible explanations for the occurrence of the identified associations, other than the etiological hypothesis originally advanced, are discussed.