This paper presents the results of research on the susceptibility of certain cultivar to fungal diseases during olive storage. Olive fruits were harvested from October to December of 2019. All fruits were collected from the same olive grove, thus excluding the influence of geographical location on the occurrence of certain fungal infections. The olive grove is located in the area of Vela Luka and it does not implement a program olives protect from diseases and pests that attack olives. The visual inspection method of fruit determined the effect of the time and method of harvesting on the occurrence of fungal causes of fruit spoilage. Fruits obtained by hand harvesting have a higher percentage of healthy fruits compared to those obtained by mechanical harvesting. Harvest during the first period gives a higher percentage of healthy fruit than harvest during the second and third periods. Cultivars Lastovka, Drobnica and Oblica show different susceptibility to fungal diseases, so Lastovka can be characterized as the most resistant, and Oblica as the most susceptible cultivar. Mycological analysis revealed the presence of several types of fungal pathogens: Fusarium spp., Penicillium spp., Botryosphaeria sp., Alternaria spp., Colletotrichum sp. and Pseudocercosporella spp. The most common cause of fungal diseases in all fruits are Fusarium spp. and Penicillium spp. The presence of the genus Botryosphaeria sp. was found on samples of cultivars Lastovka and Oblica, Alternaria spp. on cultivar Drobnica, Colletotrichum sp. of the cultivars Oblica and Pseudocercosporella spp. of the cultivar Lastovka.