This study investigated the biochemical properties of the essential oil of the corm of Cyperus esculentus, as well as its antifungal activity on some dermatophytes and storage fungi. Also, the effect of the fungi on the biochemical properties of artificially-infected oil after 14 days of incubation was determined. The moisture content of the cormwas 27.30 ± 0.41% and oil yield was 15.44 ± 0.38% g-1. The essential oil was edible and non-rancid with free fatty acid value of 3.25 ± 0.27%; peroxide value of 5.26 ± 0.14 meq kg-1, refractive index at 40°C of 1.47 ± 0.70, saponification value of 972.05 ± 26.81 mg KOH g-1, and unsaponifiable matter 61.70 ± 1.32 g kg-1. The fungi artificially inoculated on the oil changed its biochemical properties, turning the oil rancid. The oil showed significant antifungal activity, although below the 10 mm standard for a good inhibition except for Trichophyton mentagrophytes which was 11.29 ± 0.24 mm. The antifungal activity of the orthodox antibiotic, mycostatin, was significantly higher than that of the oil on the fungi tested.