The constituents of the essential oil isolated by hydrodistillation of the aerial parts of Ruta graveolens L obtained from Mekelle, Northern Ethiopia was examined by GC-MS. The yield of the extracted oil was found to be 0.5% (v/w) on dried weight basis. A total of 13 components were identified accounting for 99.98% of the oil. The major components identified were Undecanone-2 (43.66%), Nonan-2-one (16.09%), 2-Acetoxy tetradecanone (14.49%) and Nonyl cyclopropanecarboxylate (9.22%).