Fungal infections in immunocompromised hosts are common and are associated with significant mortality and morbidity. These are endemic, caused by ubiquitous fungi such as: Histoplasma capsulatum and Mucor spps or opportunistic fungi such as: Candida species, Aspergillus species, pneumocystic jirovecii and Cyptococcus neoformans. Opportunistic fungal infections are the most common fungal infections seen in the immunocompromised and are attributed to declines in CD4+ T-cell counts, neutrophil counts, and general immunity. They have been found in patients with HIV, those who have undergone extensive surgery, in patients with hematologic disorders, and in those receiving corticosteroids, cytotoxic, or suppressive chemotherapy. As a result, infections such as candidiasis, cryptococcosis, pneumocystis pneumonia and aspergillosis spread in these hosts. Candidiasis is commonly caused by Candida albicans, a normal oral flora in the genitourinary tract, gastrointestinal tract, and on the skin. It forms biofilm on any surface and causes mucosal and systemic infections in immunocompromised hosts, widespread as: oral thrush, vulvovaginitis and endocarditis, among others. Although Candida albicans remains the leading cause of nosocomial infections, other non-albicans Candida species such as: Candida glabrata, Candida tropicalis and Candida parapsilosis are becoming increasingly common. According to Pfaller et al., 2007, Candida glabrata was the second cause of invasive infections in the United States while the ARTEMIS Global Antifungal Surveillance Program revealed that Candida albicans caused the largest number of fungal infections in the world, followed by Candida glabrata, Candida tropicalis and Candida parapsilosis respectively. The main predisposing factor... in the center of the article... However, infections related to aspergillosis, namely: endophthalmitis, endocarditis and abscesses in the myocardium, kidneys, liver, spleen, soft tissues and bones, may occur occur. (Reference). These infections may progress rapidly in severely immunosuppressed hosts such as: leukemia patients, patients receiving corticosteroids or cytotoxic therapy, and those who have recently undergone bone marrow transplantation, or patients with advanced AIDS or chronic granulomatous disease. As a result, fever, invasion of blood vessels causing multifocal infiltrates, and spread to the central nervous system may occur [76]. The fungus evades the host's immune system to cause disease through the expression of multiple gene products such as: cell wall assembly, conidia germination, hyphal elongation and growth, resistance to oxidative stress, and nutrient acquisition, among others..