Abstract: The experiment was conducted to determine the effect of Symbion-P as bio-fertilizer containing Bacillus megaterium var. phosphaticum on plant growth, yield and fruit quality of tomato plants (cv. Naram F1) grown in greenhouse conditions and to determine the efficiency of different doses of Symbion-P. The study was carried out under polyethylene (PE) covered greenhouse of Agrobest Group, in Gaziler Village (Kepez-Antalya) during the winter-summer season of 2014. Three different doses of Symbion-P were used as treatments: suggested dose (D, 300 ml da-1), half of suggested dose (D/2, 150 ml da-1) and two fold of suggested dose (Dx2, 600 ml da-1), and non-inoculated plants (0.0 ml da-1) were put on trial as control group. Symbion-P was applied twice: at transplanting time and 15 days after transplanting via irrigation lines. All plants were transplanted on January 1, 2014 as 2 plants per m2. The experiment was terminated on June 30, 2014 when plants were at the 6th trusses stage. The experimental design was randomized parcel with 4 replicates and parameters related to plant growth (plant height, stem diameter, fresh and dry weights of vegetable part and fruit), yield (first flowering time, total and marketable yield, total fruit number and average fruit weight) and fruit quality (colour, firmness, dry weight, total solube solids, titratable acidity, EC, pH, vitamin C and nitrate content) were determined. The results showed that plant growth, total and marketable yield increased by the application of biofertilizer; yields increased with increasing doses and the application of 600 ml per da (Dx2) was found the most appropriate dose for better yield and quality.