Early diagnosis of fungal infections and the implementation of appropriate treatment represent major issues for clinicians, nowadays. Histopathological demonstration of microorganisms in tissue specimens or growth of fungal agents in culture media is still considered the “gold standard”, but obtaining such specimens may be difficult. Several groups have investigated serological assays for cell wall elements unique to fungal organisms in serum or other body fluids to improve diagnostics in patients with haematological malignancies or undergoing haematopoietic stem-cell transplantation. In this review we have concentrated on the currently available assays allowing for detection of highly immunogenic components of fungal cell wall: galactomannan, mannan, and also (1→3)-β-D-glucan. Rapid serological tests appear to be useful for screening high-risk haematological patients, since they allow for the early diagnosis of invasive fungal infections, including infections with the most common pathogens such as Aspergillus and Candida. Based on current literature, factors increasing the probability of obtaining false-positive or false-negative results detected by each test were also analysed and tabulated.