A water culture technique was carried out in Soil Science Department, Faculty of Agriculture, Menoufia university winter season 2015 to study boron and nitrogen requirements and their effect on barely plants grown in a complete nutrient solution containing N at levels of 0, 30, 60 and 90 mg L^-1 and B at levels of 0, 2, 3, 6 and 9 mg L^-1. At 42 days age, plants were harvested, divided into roots and shoots, air and oven dried and weighed to obtain fresh and dry matter yield of shoots and roots. The dried plant materials were analyzed for its content of N, P, K and B. The obtained results showed that the best growth (high dry matter yield) of barley shoots was obtained at 60 mg L^-1 N and 2 mg L^-1 B. For roots, increasing B concentrations in the culture showed negative effect on root dry matter yield. Application of B increased markedly B uptake by shoots and roots. Also, application of N increased B uptake by shoots and roots and seemed to reduce the injurious effect of B. Moreover, uptake of nitrogen by shoots and roots increased progressively with increasing N levels and B concentration up to 2 mg L^-1. The results also indicated that, uptake of P and K tended to increase with increasing B concentration in the range of 2 to 3 mg L^-1. Further increase in B rates decreased the uptake of P and K by plant.