During the past years, progress has been made in the treatment of patients with cancer, and the proportion of patients achieving a complete remission and longer survival has increased. However, fungal infections have become one the leading factors contributing to morbidity and mortalitiy in patient with heamatological malignancies and solid tumours. Most opportunistic fungal infections are caused by Candida and Aspergillus species, but a growing number of less frequent fungal pathogens has been observed in recent years. The management of patients consist of a multidisciplinary approach combining radiology, new techniques in laboratory diagnostics such as serology and PCR as well as use of a growing armentarium of antifungal agents. Therapy of invasive mycosis no more rely on amphotericin B, but newer antifungal agents such as voriconazole and caspofungin have the potential to substitute the current standard therapy.