Antifungal potential of aqueous extracts of Brassica campestris L. was evaluated against three plant pathogenic fungi namely Fusarium oxysporum Schlechtend, Drechslera australiensis (Bugnic) Subram & B.L. Jain. and Macrophomina phaseolina Tassi Goid.  Aqueous extract of leaves of B. campestris was prepared and added in the potato dextrose broth medium to get 2, 4, 6, 8 and 10% concentrations (w/v). Growth of all the test fungi was significantly suppressed by higher concentration of aqueous extract of root and shoot of the test plant. Maximum biomass reduction (44%) was due to 10% root extract against M. phaseolina followed by 30% reduction in biomass of F. oxysporum. Minimum reduction in biomass (14%) was recorded in D. australiensis at 10% concentration. Shoot extract also reduced fungal biomass which was 38% in M. phaseolina, 26% in F. oxysporum and 9% in D. australiensis.