Aspergillus-associated diseases are rare and pose challenges for practitioners. Diagnosis is complex and requires rational, targeted, and multidisciplinary collaboration, as well as a high degree of expertise and an individualized approach. For the infectious diseases physician, the focus is on the question of infection or colonization. In severely immunocompromised patients, invasive aspergillosis occurs, which most frequently affects the lungs (IPA) and is characterized by invasive, destructive growth. This acute clinical picture is associated with a high mortality rate. Chronic pulmonary aspergillosis (CPA) develops on the basis of pre-existing changes in lung structure caused by other pulmonary diseases and often requires surgical treatment. Another chronic form is allergic bronchopulmonary aspergillosis (ABPA). It is often associated with bronchiectasis in patients with bronchial asthma or cystic fibrosis. Sinus mycoses are divided into non-invasive and invasive forms, which can occur in immunocompromised patients and most commonly affect the maxillary sinus. Here, local surgical measures are an obligatory part of treatment, whereas the non-invasive form usually has an allergic component. In addition, drug-based antifungal and/or anti-inflammatory therapy is used for all entities.