The new coronavirus infection severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the natural epidemic rise of respiratory infections can occur in combination with them. This report aimed to answer the question that arises regarding features of clinical and laboratory diagnostic characteristics of mixed infections. A group of patients was analyzed with combined course of acute coronavirus infection SARS-CoV-2 and influenza using clinical and laboratory instrumental data. Attention is drawn to the fact that combined course of these nosologies, characterized by a significant decrease in blood oxygen saturation with atmospheric air breathing and moderately pronounced changes of the chest organs according to computed tomography results goes together with a moderate course of the disease. Absolute lymphopenia and high C-reactive protein and fibrinogen levels may be specific markers that confirm viral etiology of this disease. At the same time, high titer of antibodies to SARS-CoV-2 did not always correspond to the full elimination of coronavirus from the body in patients with mixed infection.