Background.- Invasive mycoses are deep seated fungal infections involving mucosa and penetrate host tissues. This term actually covers “subcutaneous” and “systemic mycoses”. The virulence factors of the fungus and host immune status play role in the pathogenesis of invasive mycoses. Fungus that possess high virulence causes diseases in immunocompetent individuals. Invazive fungal infections due to low virulence opportunistic fungi are associated with increased morbidity and mortality in immunocompromised patients. Some of these pathogens show resistance to currently available antifungal agents. Understanding the risk factors associated with deep fungal infection may facilitate identification of high risk patients and guide appropriate initiation of antifungal therapy.This paper briefly reviews current knowledge of the changing epidemiology for invasive mycoses, controversial considerations about antifungal prophylaxis, and current status of antifungal susceptibility tests.* Anahtar Kelimeler: Derin mikoz, Antifungal profilaksi,Duyarlılık deneyleri*Key Words: Invasive mycoses, Antifungal prophylaxis, Susceptibility tests