Garlic (Allium sativum L.) is one of the most important crops in Egypt due to its high medical and nutritive values which were affected negatively by the excessive use in mineral nitrogen fertilizers and irrigation too. For this purpose, two field experiments were carried out during the successive winter seasons of 2015/2016 and 2016/2017 at a private farm in Besendela Village, Belqas District, Dakahlia Governorate, Egypt (31° 20' 326.7" N and 31° 45' 286.0" E) to assess the effect of mineral N fertilization (at three rates 72, 96, 120 kg N fed-1) and some organic materials (control, 10 m3 compost and 4 kg potassium-humate "KH" fed-1) under different irrigation intervals (15, 20 and 25 days) on plant growth, yield, quality, nutrients uptake of garlic and soil fertility. Treatments were arranged in Strip-Split Plot Design with three replicates; irrigation treatments in the strip plots; organic materials in the main plots, and rates of nitrogen fertilizer in the split plots. Results demonstrated that, treatments and their interactions improved soil fertility indices (available N, P, K, Fe, Mn and Zn and organic matter content). Besides plant growth characters and its nutrients content, garlic yield and its nutritive values (N, P, K, S, Ca, Fe, Mn and Zn contents) showed significant increase with the application of organic materials and increasing N rates under irrigation intervals. Interactions among treatments had significant effect on most of parameters under study, with superior the interactions impact of the N-rate 96 kg N fed-1 either with compost or KH under irrigation every 20 days. For the yield quality; bulbs content of dry matter, sulfur and pungency enhanced with the applications of compost or KH alongside with mineral N fertilization up to 96 kg N fed-1, moreover its content of nitrate was decreased. On the other hand, quality indices declined with increasing the application rate of mineral N fertilizer up to 120 kg N fed-1, and accumulation of nitrate in bulbs increased. It could be concluded that application of compost or KH along with mineral nitrogen fertilizer at the rate of 96 kg N fed-1 with irrigation the plants every 20 days had favorable effect on the most studied traits of garlic yield and quality.