A pot experiment was conducted at the Experimental Station Farm, Faculty of Agriculture, Mansoura University during the winter season of 2013/2014 to investigate the effect of phosphorus, nitrogen and copper fertilization on yield and nutrients uptake of onion (Allium cepa L.).The experiment was carried out in factorial experiment in complete randomized block design (CRBD) with three replications. The obtained results could be summarized as the following: -    Fertilizing onion plants with the highest level of phosphorus fertilizer (100 kg P₂O₅ fed^-1) produced the highest values of all studied characters in the season. -    Application of the highest level of nitrogen fertilizer (150 kg N fed^-1) produced the highest values of yield, quality and nutrients uptake characters of onion in the season. -    Foliar spraying of onion plants with Cu at rate of 50 ppm significantly surpassed control treatment (without spraying with Cu) and produced the highest values of all studied characters in the season. It can be concluded that fertilizing onion plants with 100 kg P₂O₅ fed^-1 and 150 kg N fed^-1 in addition to foliar spraying with 50 ppm Cu in the form of CuSO₄ at three times in order to maximizing its yield, quality and nutrients uptake under the environmental conditions of Mansoura district, Dakahlia Governorate, Egypt.