Purpose Farming is a high-pressure occupation. Populations of farmers face significant health risks, including injury, mental illness, and in some cases, heavy alcohol use. However, there is little research on farmers’ use of substances beyond alcohol. This study examines factors relating to Irish farmers’ disordered alcohol and substance use. Methods In accordance with STROBE guidelines for cross-sectional research and reporting, we examined disordered alcohol and substance use in 351 Irish farmers using the Alcohol Use Disorders Identification Tool (AUDIT) and Drug Use Disorders Identification Tool (DUDIT). Findings While 28% of farmers did not drink, 40% of those who did drink exceeded the AUDIT threshold for disordered use. Similarly, while 95% of farmers did not use substances, 78% of farmers who did use substances exceeded the DUDIT threshold for disordered use. Age was the most important risk factor for disordered alcohol and substance use and correlated with other main risk factors: lower income, no children, part-time farmer, and full-time off-farm roles. Disordered drinking was highest in farmers engaged in full-time education. Conclusions This population of Irish farmers report broadly healthy alcohol and substance use behaviors. Irish farmers may serve as a model group whose strengths can be utilized in interventions within and beyond the Irish farming community. Our results confirm the importance of analyzing demographic factors in farmers’ drinking and identify younger farmers as especially at-risk for harmful alcohol and substance use.