The pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was primarily focused on the involvement of the respiratory system, as the most common clinical manifestation of the disease. Currently, also long COVID poses a significant problem for medicine and public health worldwide. It is characterized by persistent symptoms from various organs or systems, often present for several weeks and months after acute phase of SARS-CoV-2 infection. Currently, the most frequently used description for long COVID referred to symptoms that last more than three months after the onset. Numerous data confirm long-term effects of COVID-19, including pulmonary, cardiovascular, neurological, renal, hematologic, gastrointestinal, endocrine and psychosocial manifestations. It is necessary to monitor patients after acute phase of COVID-19 to detect and treat possible multi-organ long-term consequences of SARS-CoV-2 infection.