The number of patients with immunosuppression is rising worldwide. The spectrum of diseases and pathogens in these patients differs widely from that of immunocompetent patients due to frequent opportunistic infections. Symptoms are sometimes unspecific, and imaging plays a key role in the management of these patients. The lungs are a frequent site of infection in immunosuppressed patients. Chest X‑ray is the starting point for radiological diagnostics, but shows only limited sensitivity and specificity for infections with atypical pathogens. Thus, computed tomography (CT) is of great importance and allows a better distinction between viral, bacterial, or fungal infections, as well as other noninfectious diseases. Even with CT, however, is exact specification of the pathogen unfortunately not possible. CT is also the main diagnostic tool for assessment of the abdomen, particularly in patients presenting with acute abdomen or when sonographic findings are inconclusive. Moreover, CT allows diagnostic and therapeutic interventions such as percutaneous biopsies, or abscess and fluid drainage.