Abstract: Two field experiments were carried out during two successive seasons of 2011 and 2012 to study the effect of bio- and chemical fertilizers on growth, flowering and some chemical analysis of Petunia Hybrida (cv. Bravo White). Petunia plants were sprayed with Azospirillum lipoferum (nitrogen fixing bacteria, N.F.B.) and Bacillus polymxa (phosphate dissolving bacteria, P.D.B.) and their mixture in presence or absence of a complete fertilizer of 19N: 19P2 O5 : 19K2 O. Both bacterial inoculants and their mixture showed significantly increases in the studied vegetative growth (i.e., plant height, branches number, leaf area, dry weights of shoots and roots) and flower parameters (i.e. flowering date, number of flower/branch and flowering period) when compared with the control (full dose of NPK chemical fertilizer = 5 g plant-1 twice). Also the results revealed that using Azospirillum sp. + Bacillus sp. plus 5 g plant-1 of the chemical fertilizer produced the highest significant values of all growth, flowering parameters and chemical analysis (chlorophyll, total carbohydrates, N and P percentages) compared with the control. It was clear that biofertilizers beside its ability to improve the nutrient supply in the soil, they also increased the efficiency of added chemical fertilizer. From the obtained results it can be used the half dose of the recommended chemical fertilizer (2.5 g plant-1 twice) combined with each of nitrogen fixing bacteria (at 2 mL L-1 twice) and phosphate dissolving bacteria (at 2 mL L-1 twice) to grow Petunia hybrid cv. Bravo White with high quality, reducing the environmental from pollution and surpassed the recommended dose of the chemical fertilizer.