A hospital-based cross-sectional case-control study was conducted to investigate the association between exposure through various pesticide residues detected in the plasma and serum 8-OHdG levels among farmers and non-farmers diagnosed with leukaemia, lymphoma and breast cancers and compare the same with healthy controls with no cancer and no exposure. The present study was conducted among the farmers and non-farmers visiting a regional tertiary cancer care hospital in Hyderabad, Telangana State, India. Data were collected by administering a pre-tested questionnaire through an interview followed by the collection of blood samples which were analyzed for pesticide residues using LC-MS/MS while the serum levels of 8-OHdG were measured using ELISA. Data were analyzed using SPSS 24. The pesticide residues detected were chlorpyrifos, dimethoate, malathion, phosalone, and quinalphos which were approved and recommended for their use on the crops that were cultivated by the farmers in their plasma samples along with banned pesticide residues like monocrotophos, diazinon, and dichlorvos among farmers diagnosed with all three types of cancers while the non-farmers and healthy controls were not detected with any such residues. In addition, farmers diagnosed with leukemia had higher levels of all the pesticide residues in their plasma than those diagnosed with lymphoma and breast cancers. Further, a significant difference was also observed between profenofos residues in plasma and serum 8-OHdG levels. In the present study, though the farmers diagnosed with three types of cancers were detected with various types of pesticide residues analysed, only residues of profenofos showed a significant difference with serum levels of 8-OHdG suggesting the need for an in-depth follow up molecular studies in a larger cohort to assess the possible association between 8-OHdG levels with the pesticide residues among the exposed.