The present study was conducted at Barrage Horticultural Research Station, Kalubia Governorate. Two field experiments were carried out during seasons of 2004 and 2005 to study the effect of nitrogen sources , nitrogen levels and defoliation on growth and corm yield, as well as some chemical constituents, of the local cv. Balady of taro plant. Three nitrogen sources. i.e. ammonium sulphate , ammonium nitrate  and urea with three nitrogen levels (40,80 and 160 Kg N/Fed.) and defoliation ( leaving 4,5,6 leaves/plant) , as well as the control (not leaves removing) were used. Results showed that the application of nitrogen in the form of ammonium sulphate increased plant height, fresh weight/plant, total yield/plot, corm length and corm diameter. The results also indicated that plant height, leaf area, chlorophyll content, fresh weight/ plant, total yield/plot, corm length, and corm diameter increased with increasing nitrogen application up to 80 Kg N/Fed. Morever, defoliation of the (6 leaves and the control) gave the highest values in all characters expect the chlorophyll leaf content, diameter corm and dry matter percentage. Starch percentage of corms increased with increasing nitrogen level up to 80 Kg N/Fed., in the form of urea in addition to the control, while, nitrogen and protein percentage of corms increased with increasing nitrogen level up to 160 Kg N/Fed. in the form of ammonium nitrate and the control one.