The study was conducted as attempt to obtain genetically modified Azotobacter vinilandii isolate able to fix nitrogen and dissolve phosphate at the same time and used different biological activity parameters (Bacterial count, relatively growth rate, available phosphorus in soil and amount of fixed nitrogen ) to compare between genetically and non-genetically modified A. vinilandii isolates.The transferring of a plasmid coding for dissolving phosphate were made according to Sam brook etal (1) to transfer the plasmid from local isolate of P.aeruginosa to local isolate of A. vinilandii. Results showed the superiority of genetically modified A. vinilandii was the best in all the parameter used above in comparison with the original selected local isolates (P. aeruginosa and A. vinilandii).Inoculation of soil with genetically modified A. vinilandii increase significantly (P<0.05) the available phosphorus was 28.1 mg/kg soil after 45 days inoculation in compare with non-genetically modified A. vinilandii which gave 16.2 mgkg available phosphorus.The efficiency of nitrogen fixation increased with modified genetically A. vinilandii isolate and reach to 157 mg total nitrogen /kg soil after 45 days of it incubation in soil while 130 mg total nitrogen /kg soil was recorded with the original A. vinilandii isolate. Results showed that all parameters which were used in the present study decreased when culture of the original isolate of (P. aeruginosa and A. vinilandii) were mixed and used.