Systemic candidiasis is a disease of increasing incidence and proportions, which appears to be associated with the advances in modern medicine. It involves primarily patients with severe debilitating and malignant disease who are receiving immunosuppressive, cytotoxic, antimetabolite, and antibiotic therapy. Side effects of these otherwise major therapeutic agents predispose patients to opportunistic fungal infections, of which candidiasis is the most common. The high morbidity and mortality of disseminated candidiasis in neutropenic patients are difficult obstacles to obtaining the optimal, if not full, potential of modern chemotherapy for cancer. The inability to diagnose early invasive and systemic candidiasis is a major handicap that delays timely initiation of antifungal therapy. The paucity of highly efficacious antifungal agents with low toxicity severely limits the ability to successfully cure systemic fungal infections in cancer patients. Aggressive research into the basic biology of Candida spp. is necessary for directing the development of better diagnostic methods and improved antifungal drugs.