Two field experiment were carried out in the Experimental Farm of Sids Horticulture Research Station Beni-Sueif Governorate in summer seasons of 2011 and 2012 to study the response of tomato plants cv. (strain B) to microbein inoculation treatments, i.e. without , one dose at the time of transplanting or two doses at the time of transplanting and 20 days later and nitrogen fertilizer at the rates of 60, 80, 100 and 120Kg N/ fed combined with organic manure as compost at the rate of  4, 6, 8 and 10 t / fed. The obtained results showed that inoculation with microbein at two doses improved plant height, number of branches, plant dry weight, total chlorophyll, N, P and K contents of leaves, total fruit yield and its components, fruit dry matter percentage, fruit length and diameter, fruit thickness and TSS% in the two growing seasons, and also it increased Vit. C in the first season, as compared to one dose or control treatments.