Garlic (Allium sativum L.) is an important plant because of its medicinal and gastronomical benefits. The host can be affected by different plant pathogens, among which Penicillium species are one of the most important rot agents, of stored garlic and other stored food products. This research resolves the etiology of blue mold rots associated with garlic in Serbia. Penicillium-like isolates were collected (2016-2022) from diseased stored garlic bulbs in Serbia and identified using a polyphasic approach. Detailed characterization of the obtained cultures was performed using three solid media, three incubation temperatures, molecular and phylogenetic analyses of four molecular loci [internal transcribed spacer (ITS), beta-tubulin (BenA), calmodulin (CaM) and DNA-dependent RNA polymerase II second largest subunit (RPB2)] and the pathogenicity assay. Five Penicillium species, i.e. P. allii, P. glabrum, P. italicum, P. polonicum, and P. psychrotrophicum were identified and confirmed as postharvest pathogens of garlic. Herein, we report for the first time the pathogenicity of P. psychrotrophicum and P. italicum on garlic. Findings from this study provide insights into the previously unknown diversity of Penicillium fungi responsible for garlic bulb decay in Serbia, and will help in the assessment of the phytosanitary status of this crop, as well as the creation and application of effective disease management strategies.