Five strains of Agrobacterium tumefaciens were isolated and characterized from 12 different plant tumors. The susceptibility of these phytopathogens to antibiotics and to soil Streptomyces isolates was tested. Among the 90 Streptomyces isolates, only 12 were able to inhibit the growth of at least one A. tumefaciens strain. Four strains of A. tumefaciens were susceptible to streptomycin and cefotaxime. In addition, Streptomyces 404 strain was able to inhibit the growth of four strains of the Agrobacterium pathogens with an inhibition zone diameter ranged between 10 and 16 mm. The strong inhibitory effects of Streptomyces 404 strain on A. tumefaciens suggest the use of this strain as a promising agent to control crown gall disease.