Fusarium oxysporum (Schlecht Nedan); Rhizoctonia solani (Kuhn), Macrophomina phaseolina (Tassi) and Sclerotium rolfsii are found to be pathogenic to soybean causing damping off, root rot and wilt diseases resulting in serious economic losses. Biofumigation is used as a means to control many diseases by biocidal compounds (mainly isothiocyanates) released from glucosinolates in mustardseed meal is hydrolyzed during incorporation in the soil.                 Laboratory, pots and field experiments were conducted to evaluate the efficacy of mustard (Brassica juncea (L.) seed meal on control by soil borne pathogens. In laboratory experiments, mustard seed meal decreased the linear growth of the tested fungi as compared with the control. The fungicidal effect of mustard seed meal against the tested fungiwas demonstrated in pot experiments: diseases were suppressed and plant growth was increased compared to untreated (control). Similar control effect was also obtained in filed experiment conducted in Ismailia, Agric. Res. Station. The obtained results indicated that mustard seed meal reduced the disease incidence over control by 69.7 % when recorded 4 months after planting. On the other hand, the reduction reached 74.4% over control by Rhizolex treatments when recorded 4 months after planting.