The present investigation was carried out in the Experimental Station of the Medicinal and Aromatic Plants, Fac. Agric., Mansoura Univ., during the two seasons of 2008 / 2009 and 2009 / 2010 to study the effect of foliar humic acid application and fertilizers types; N₂₀₀P₂₀₀K₅₀ (kg / fed) recommended dose (RD), compost and cattle manure at rates of (10, 15 and 20 m³ / fed) in addition to their interaction on vegetative growth, fruits yield and essential oil quality  of fennel (Foeniculum Vulgare Mill.) plants. The results indicated that, foliar humic acid application at 10 cm / L had a positive effect on vegetative growth, expressed as plant height, plant dry weight, number of days till harvesting, essential oil percentage, oil yield and the main component estragole was increased significantly in comparison with treatment plants without humic acid. The best results were of fennel plants which received N₂₀₀P₂₀₀K₅₀ kg / fed (RD) followed by compost at rate of 20 m³ / fed, when compared with other plants treated by fertilizers separately. The combined treatment of NPK (RD) followed by the medium compost dose (15 m³/ fed) and foliar humic acid application were more effective on all traits studied than each individual or combination treatments with humic acid in both seasons. The G.L.C. of the essential oil revealed a total of 7 compounds which represent from 92.73 to 99.05 %. These components are α-pinene, myrcene, limonene, fenchone, 1.8- cineole, estragole and anethole. The major component is estragole which represent from 65.72 % to 91.46 %.