Invasive candidiasis is an infection of increasing prevalence which is associated with high morbidity and mortality. The rising incidence of invasive candidiasis is likely related to increasing numbers of immuno-compromised patients and lifesaving medical/surgical interventions that prolong life but break down both immunological and physical host defenses. The available tests include serologies focusing on the fungal cell wall components mannan, galactomannan, and (1,3)-ß-d-glucan (BG) or antibodies against these antigens, as well as genetic material detection tests. This chapter focuses on these new markers and their use for advanced prevention and treatment strategies. Research has shown that BG levels are not affected by Candida colonization. Aside from BG, which is currently commercially available throughout the world, there is intense research for new biomarkers. This is driven by the fact that current diagnostic methods are less than optimal, by the interest of pharmaceutical companies in finding new surrogate markers for diagnosis and outcomes assessment for drug development trials, and by the recent interest of commercial diagnostic laboratories in these methods. Antifungal prophylaxis is an attractive strategy, as the best way to deal with a fungal infection is to prevent it from ever occurring.