Cyanobacteria are one of important groups of prokaryotes  due to their effects on growth and development of plants and its role in biological control of  phytopathogenic  fungi  such as :  Fusarium oxysporum and Rhizoctonia solani  on flax  by producing various biologically active substances . In the present study , fourteen  cyanobacterial strains were isolated from rice rhizosphere in kafr El–sheikh (k) ( North Delta Region ) and El- Dakahliya (D) ( East Delta Region ) . Only five cyanobacterial strains showed antagonistic effects against the both pathogenic fungi and were indentified as Nostoc muscorum k , Anabaena oryzae D , Anabaena oryzae k , Nostoc pruniforme D and Oscillatoria brevis D. The strains  were analysed  for phosphate  solubilization , production  of  IAA , ammonia , HCN , production  of some enzymes , and effect of their filterates on seed germination of flax seeds . Flax seeds treated with cyanobacterial filtrates germinated  faster and produced higher seedlings compared with  the nontreated ones .