Introduction. Some oral mucosal diseases appear as a result of immunodeficiency of the organism caused by systemic diseases. In recent years, it has been shown that chronic hepatitis B and C infection, in addition to causing liver disease, is also responsible for several extrahepatic manifestations and immune abnormalities. Chronic viral hepatitis B and C was found to be involved in the pathogenesis of some oral diseases. The diagnostic process includes some sequential steps to elucidate the cause itself and to provide an adequate plan of treatment.  Aim of the study. To provide general aspects in diagnosis of oral mucosal diseases of the patients with chronic viral hepatitis B and C using the review from literature.  Materials and methods. The dates found in five scientific articles from different countries were selected in this study. An overview from literature on the diagnosis data of the oral mucosal diseases of the patients with chronic viral hepatitis B and C was done. Results. The analyzis of the methods used to diagnose the oral mucosal diseases revealed the important role of knowing their etiology on establishing the correct treatment plan. Besides the clinical diagnostic, a big importance in diagnosis has the paraclinical examination, which includes: biopsy of the affected tissues, microbiological tests, radiological examinations, immunofluorescence tests. In addition to these examinations, the tests for chronic viral hepatitis B and C have to be done, such as: serologic examination (hepatic markers), molecular-biological and immunologic testes.  Conclusions. According to the five scientific articles, the diagnosis of oral mucosal diseases of the patients with chronic viral hepatitis B and C involves four sequential steps: 1. obtaining of comprehensive overview of the patient’s local and general status; 2. evaluation of all the findings to correlate the chief sight of symptoms with the current history, 3. physical findings and medical history; 4. establishment of differential diagnosis.