The purpose of this study was test the effect of the Origanum vulgare essential oil on the micelial growth of the rice pathogenic fungi. Micelium discs of the fungi Alternaria sp., Bipolaris oryzae, Curvularia sp., Gerlachia oryzae, Rhizoctonia solani and clerotinia sclerotiorum were placed in the center of Petry plates with PDA and oil in different concentrations: pure oil, 1:2, 1:4, 1:8, 1:16, 1:32 which was incubated to 22 ± 2°C under 12 h photoperiod, until the control (Potato-Dextrose-Agar + ethanol) fill all the plate. All genera showed reduction in the micelial growth. B. oryzae was the most sensible, with statistic difference in all concentrations.