In New Zealand, farming occupations have consistently been associated with an increased risk of non-Hodgkin lymphoma (NHL). Pesticide exposure is likely to play a role, but the specific causal agents have yet to be identified. This study will investigate whether farmers currently applying pesticides in New Zealand continue to be at an increased risk of NHL by assessing biomarkers hypothesised to be on the causal pathway to the disease. Blood will be collected from farmers applying different pesticides (n=100), as well as a non-exposed group (n=50), and tested for specific genotoxic, epigenetic and immunotoxic changes. The prevalence and frequency of these biomarkers will be compared between the exposed and non-exposed groups, and within the exposed groups before and after pesticide application. This study will provide timely insights into which currently used pesticides and spraying practices are associated with biomarkers of elevated NHL risk, thereby providing opportunities for intervention and prevention.