This research was conducted to determine the effect of bacterial strains isolated from different sources on the development of melon plants. Plant growth promotion mechanisms such as calcium, potassium and phosphorus solubilization, nitrogen fixation, phytohormone, siderophore and ACC-deaminase production and their growth at different pH and salt concentrations were determined. In order to determine the effect of bacterial strains on plant growth, field trials were established according to the randomized blocks experimental design with three replicates and carried out with two years of repetition. In the experiment established for this purpose, 11 different applications [IT 22 (Bacillus safensis), IT 22 + Fertilizer, IT 63 (Acinetobacter calcoaceticus), IT 63 + Fertilizer, IT 93 (Acinetobacter calcoaceticus), IT 93 + Fertilizer, IT 115 (Serratia rubidaea), IT 115 + Fertilizer and control (fertilizer only)] were included. In terms of all parameters examined, the best result was obtained from the Mix + Fertilizer application, while only the highest value of WSDM (9.9%) was measured in the IT 93 + Fertilizer application. The results of the study show that fertilizer-free IT 93 and Mix applications provide higher melon yield than fertilizer, suggesting that bacterial single or mixed applications can be used as a very effective method to reduce the use of chemical fertilizers. In addition, higher fruit yield per decare was obtained in the blocks where bacteria and fertilizer were applied together, except for IT 115 + Fertilizer application, compared to the control group. This result was an indication that a significant reduction in chemical use will be achieved with the inclusion of the determined bacterial strains in fertilization programs.