We report on a case of a 19-year-old female patient with acute promyelocytic leukemia suffering from febrile monarthitis of the right knee during neutropenia after consolidation chemotherapy caused by Geotrichum capitatum. Apparently this infection occurred due to a hematological reactivation since the patient had already developed Geotrichum capitatum fungemia during induction therapy. Under antimycotic therapy with voriconazole, flucytosine, and caspofungin as well as after two arthroscopic synovectomies with cleansing of the right knee, the infection could be controlled and the full clinical function of the knee joint could be preserved.