Two field trials were conducted at Sers EL-Lian Experiment Station during 2006/2007 and 2007/2008 to study the effect of fahl berseem mixed with wheat under three densities of fahl berseem (15, 25 and 35%) of the recommended rate of fahl berseem (20 kg fed^-1). Each rate was mixed with the recommended rate of wheat seed (60 kg fed-¹) and fertilized by three rates of nitrogen fertilizer, i.e., 100% of the recommended rate of N for wheat (75 kg Nfed^-1), 75% (56.25 kg Nfed^-1) and 50% of the recommended rate (37.5 kg Nfed^-1) on growth, yield and yield components of both crops in the mixture. The data showed that all values of wheat characters significantly decreased by increasing the percentage of fahl berseem seeding rates when mixed with wheat, whereas, opposite trend was found by increasing nitrogen rates. The data also revealed that all fahl berseem characters significantly increased by increasing percentage of fahl berseem when mixed with wheat or by increasing nitrogen rates. Data also, indicated that mixing 35% of fahl berseem seeds with wheat fertilized by the recommended rate (75 kg N fed^-1) gave the best land equivalent ratio (LER) and total income. Soil sustainability increased as indicated by chemical properties of the soil. Chemical analysis revealed increased values of organic matter, available nitrogen, phosphorus and potassium when growing mixtures as compared with growing wheat only. In the 2yr, fahl berseem was more competitive than wheat.