The present study was carried out to evaluate the antifungal efficacy of essential oils (EO) of Cymbopogon martini, Chenopodium ambrosioides and of their combination against dermatophytes and some filamentous fungi in vitro as well as in vivo using a guinea pig model. The minimum inhibitory concentrations of EOs and of their combination were found between 150 and 500 ppm, while those of known antifungal drugs ranged from 1000 to 5500 ppm. EO ointments were prepared and applied against induced ringworm in guinea pig model and disease removal was observed in 7-21 days, and the hair samples showed negative results for fungal culture in a time-dependent manner after the application of EO ointments. Chemical constituents of EOs were determined by GC-MS. Both the EOs and their combination displayed strong antifungal effects. The results provide a scientific validation for the use of these EOs in the treatment of dermatophyte infections and may be recommended as an alternative to synthetic drug for topical application.