The antimycotic acitivities of different concentrations of the essential oil of Satureja mutica F., an endemic plant of Iran, was evaluated against four filamentous fungal and two yeast strains. The antifungal tests were conducted by a poisoned food technique against the filamentous fungi Aspergillus niger, Trichophyton rubrum, Trichoderma reesei and Microsporum gypseum, and by a microdilution assay against two yeast strains, Candida albicans and Saccharomyces cerevisiae. The essential oil was found to be fungicidal at greater than or equal to0.25 mul/ml against the filamentous fungi. The minimum inhibitory concentration of the oil against the two yeast strains was found to be 1333 ppm (1/750 v/v). As such, the oil has a potential use as an antifungal chemotherapeutic against both filamentous fungal and yeast strains after toxicity tests, clinical trials and formulation to a suitable pharmaceutical dosage form. Copyright (C) 2004 John Wiley Sons, Ltd.