The 3 leading causes of death in patients after solid organ transplantation (SOT) include cardiovascular diseases, malignancies, and infections. According to our current understanding, the latter play the key role in the pathogenesis of atherosclerosis. Similarly, infections (mainly viral) are implicated in the pathogenesis of at least 20% of known neoplasms. In other words, the implications of acute and chronic infectious diseases in modern medicine, not only transplantology, are significant and ever‑increasing. Immunosuppressive treatment impairs the immune function, which renders the patient more susceptible to infections. Furthermore, treatment of infections in immunocompromised patients poses a challenge and SOT. The current publication provides a brief summary of the key information provided in 20 lectures on viral infections in patients after SOT delivered during the 9th Practical Transplantology Course in Warsaw, Poland on September 15-16, 2017.