Essential oil of Ocimum basilicum, traditionally used for ailments of an infections or septic nature, and two of its components, linalool and limonen were tested for their antifungal activity against 12 micromycetes (Alternaria alternata, Aspergillus niger, A. ochraceus, A. versicolor, A. flavus, A. terreus, Cladosporium cladosporioides, Fusarium tricinctum, Penicillium ochrocloron, P. funiculosum, Phomopsis helianthi and Trichoderma viride). Among tested fungal species were the food poisoning species, plant, animal and human pathogen. In order to investigate antifungal activity of essential oil and two of its components, the modified mycelial growth test with malt agar was used. The oil, linalool and limonen exhibited strong inhibitory effect against all tested organisms. Phomopsis helianthi was the most susceptible micromycetes to the investigated compounds. Trichoderma viride seems to be the most resistant micromycetes treated with essential oil of O. basilicum and limonen, while Penicillium ochrocloron was the most resistant organisms in treatment with linalool.