Abstract: Tobacco related oral cancer occurs due to accumulation of genetic alterations induced by the genotoxins present in betel quid. The objective of the study was evaluate the cytogenetic damage in the peripheral blood of oral cancer patients and control subjects by anaysing the structural aberrations (STAs) .The frequency of STAs was analyzed in 60 histopathologically confirmed oral potentially malignant disorders (OPMDs) and oral squamous cell carcinoma (OSCC) patients. STAs showed a significant P value between the Controls, OPMDs & OSCC cases through ANOVA. Significant P value through t-test was also observed between the pairs of group namely Controls Vs OPMDs cases, Control Vs OSCC cases and OPMDs Vs OSCC cases. STAs showed a significant P value in the patients when compared with the controls and also showed an increased chromosomal alteration in OPMDs and further increased in OSCC thus correlating well with the clinical stages of the disease. CSAs were more than CTAs in the cases with dicentrics being more prevalent. The elevated STAs in the study group could be attributed to the fact they belong to high risk population for oral cancer. A predictor STAs identified in the present study may be used in future for early diagnosis and subsequent disease management of the tobacco related oral cancer patients.