A field experiment was conducted during the two successive seasons of 2012/2013 and 2013/2014 in El-Maghara Research Station, Desert Research Center, North Sinai Governorate to study the effect of organic fertilization and foliar spray with active dry yeast on growth, seeds yield and chemical constituents of Sinapis alba L. seeds. The experiment was carried out in split plot design. The main plots were consisted of three application levels of organic fertilization of 3, 6 and 9 ton compost per feddan. The sub-plots included foliar spray of active dry yeast at three concentrations (0, 3 and 6 g/liter). The interaction effect indicated that the application of the highest compost manure level of 9 ton/fed with foliar spray of the highest yeast concentration of 6 g/liter led significantly to the highest increments in plant height, dry weight per plant, number of siliquae per plant, seeds yield per plant and per feddan, fixed oil yield per plant and furthermore increased total protein content in the seeds over control treatment. Erucic acid was the main dominant fatty acid in fixed oil composition.