Methods of molecular genetics offer rapid and sensitive detection and identification of fungal pathogens. The currently used methods are based mainly on PCR. With regard to the ubiquitous presence of fungi, it is important to prevent contamination during the whole process, from sampling to laboratory analyses. Molecular genetic methods are not included among the EORTC/MSG criteria used for the diagnosis of invasive fungal diseases since interlaboratory standardization is still missing. Another reason is the use of different target genes for PCR. ITS sequences from rDNA clusters are recommended for DNA barcoding of fungi. The use of DNA sequencing for identification of fungi in clinical samples has certain limitations and interpretation of results could be problematic in some cases. DNA sequences are searched and compared in public databases on the Internet, the best known of them being the GenBank. However, more reliable data for identification of fungi are offered by specialized mycological databases.