The antifungal activities of essential oils from Thymus quinquecostatus and T. magnus, which are species native to Korea, were evaluated against seven common pathogenic fungi. Additionally, the effects of the oils together with ketoconazole were tested by the checkerboard titer test. Both of the two Thymus oils showed significant inhibition of the tested fungi, with minimal inhibitor concentrations (MICs) and minimal fungicidal concentrations (MFCs) in the range of 0.04-0.39 mg/mL and 0.19-0.78 mg/mL, respectively. The two Thymus oils, and thymol as well, exhibited synergism with ketoconazole against Trichophyton rubrum, which showed the highest susceptibility to these oils.