Three field experiments were carried out in the Experimental Station of Desert Research Center at Maruyt, Western Delta during 2001, 2002 and 2003 winter seasons, to study the response of two wheat cultivars for three levels of compost soil organic manure and three sUpplemental irrigation treatments under rainfed conditions, and its relation'to wheat leaf spot blotch disease incidence caused Blopoluvfs sovokinfana (syn. Helminthosporum sativum) presented under these conditions. Wheat variety Giza-155 was superior than Sakha-B in most of the studied growth characters i.e (plant heightfcm, number of tillersfplant, peduncle lengthicm number of leaves per plant, plant fresh & dry weightsig, days to heading), chemical compositions i.e. (freeiproline U molelg, bound water, total pigmentsISPDA and total chlorophyll (.1 mole m' ) and days to maturity. While Sakha-B surpassed the other wheat variety in (flag leaf arealcm2 and % of total and free water content). While significant differences between the tw0 varieties in yield and its components i.e.(biological, grain and straw yields tonlfed, no of spikes imi, spike length! cm, no spikelets and grains! spike and 1000 grain weight lg). Applying (one supplementary irrigation at heading stage + rainfed) increased significantly all studied growth characters, % total and free water, total pigmentsISPDA, total chlorophyll I pmole m'z, grain yield tonffed, spike lengthicm, no of spike-lets, no ofgrains per spike, no of Spikes fmz, 1000 grain weight lg, and days maturity more than added (one irrigation at sowing + rainfed) or under rainfed only Only free proline U molefg, and bound water % were increased significantly under rainfed irrigation. Biological and straw yields tonlfed were increased significantly applying (one supplemental irrigation at sowing date + rainfed). Adding compost as a soil amendment increased significantly wheat growth characters, chemical compositions and yield and its attributes compared with the control treatment (0 malfed). Increasing the amounts added of compost to the experimental soil had significant positive effects on encouraging the studied growth characters, chemical compositions, yield and its attributes and days to maturity, while free proline U molelg and % of bound water contents didn't show any significant response to increase compost amounts added to the experimental soil- All first and second order interactlons between treatments increased significantly every studied growth characters, chemical composition, yield and its attributes except peduncle length! cm, no. Ieaveslplant and free proline which didn respond significantly under the interaction between irrigation and compost treatments Leaf spot blotch disease which recorded as a barley disease in Egypt, infected wheat under the experimental conditions in a light degree. All treatments effected positively in reducing disease incidence.