The clinical and epidemiological features of hepatitis A in the Transcarpathian region for years 2004–2014 were indicated. A specific cyclicism and seasonality of hepatitis A in this region of Ukraine was established. Based on the examination of 61 patients with hepatitis A a peculiarity of the clinical progression of the disease, and, also, specific microbiological changes of the quantitative and qualitative composition of the colon microflora, depending on the presence of a concomitant chronic pathology of the digestive organs, were established.