A field experiment was conducted during two successive summer seasons of 2010 and 2011 at the experimental farm of Sakha Agric. Res. Station, Kafr EL-Sheikh Governorate. This study was conducted to investigate the effects of N-mineral and organic fertilizers (rice straw compost) with or without sulphur on soybean yield, its chemical composition and soil contents of N, P and K. The experiments were conducted in split plot design, where the main plots were allotted for soybean cultivars; Crowford (Cv₁), Giza111 (Cv₂), and Taiwan (Cv₃). The sub plots were allotted for fertilizer treatments:  1-N fertilizer as urea at level of 15 kg. Nfed^-1 (control treatment) 2-Rice straw compost at rate of 10tonfed^-1 ( OM), 3 –Rice straw compost at rate of 10 tonfed^-1 + sulphur at rate of 400 kgfed^-1 (OM+S), 4- N fertilizers  as urea at rate of 15 kg N fed^-1 +sulphur of400kgfed^-1 (N+S)  .The treatments were replicated four times. The results can be summarized as follows:- 1- The yield and its components of soybean were significantly affected by fertilizers treatments and soybean cultivars 2- The highest soybean biomass and seed yields were obtained by Cv₁ under OM +S treatment 3- The maximum values of N, P and K contents in the seeds were obtained by Cv₁ under OM treatment 4- The highest N and P content in straw were recorded by the control treatment, where the highest values of K content were obtained by OM +S treatment 5- N+S treatment had the highest protein content in the seeds. 6- OM treatment recorded the highest values of available N, P and K in   soil