In this study we evaluated the composition of seven high risk periodontitis species of microorganisms in the oral microbiome of patients with different forms of head and neck squamous cell carcinoma (HNSCC). The laboratory analyses were performed using the method of quantitative real-time amplification (qPCR) of 26 saliva and mouth swab samples collected from HNSCC patients. Laboratory data regarding the normal or pathological presence of studied species were integrated with patients clinical conditions and some lifestyle factors. The results show that the highest frequency of pathological concentration is in the case of Fusobacterium nucleatum and Tannerella forsythia, while the lowest frequency is observed for microorganisms Aggregatibacter actinomycetemcomitans and Treponema denticola.