The aim of this case control study was to assess the association between the extent and severity of chronic periodontitis and oral cavity and/or oropharyngeal cancer. The case group comprised 35 patients (mean age 56.1±8.4), diagnosed for oral and/or oropharyngeal cancer. The control group comprised 40 individuals (mean age 55.4±9.4) without diagnostic of cancer. All individuals were subjected to a periodontal examination, including bleeding on probing, plaque index, gingival index, probing pocket depth (PPD), clinical attachment loss (CAL), and decayed, extracted and filled teeth index (DMFT). The case group had significantly more sites with plaque. GI and BOP had similar values in both groups. The median PPD and CAL values were significantly higher for the case group. Chronic generalized periodontitis was predominant in 80% of patients with oral and/or oropharyngeal cancer. Eighty nine percent of the patients in the case group presented severe chronic periodontitis. There was no significant difference between groups for median values of DMFT. The extent and severity of chronic periodontitis remained as risk indicators for oral cavity and/or oropharyngeal cancer even after the adjustments for traditional confound factors, i.e. smoking and alcohol consumption.