Multifunctional rhizobacteria can promote enhanced root development and increase grain yield in agricultural crops. The aim of this study was to determine the effects of rhizobacteria application on the root growth of soybean, common bean, corn, and upland rice seedlings. The experiments were conducted under controlled conditions in a completely randomized design, with four treatments and ten replicates for each crop. The treatments in the four experiments consisted of the microbiolization of seeds from each crop with the following rhizobacteria isolates: BRM 32111 (Burkholderia sp.), BRM 63523 (Serratia sp.), BRM 63524 (Bacillus sp.), and a control treatment (without microorganisms). For each experimental unit, containers with a capacity of 500 mL were filled with soil and sand, and two seeds were used. After 14 days, the roots of the seedlings of the studied cultures were removed, washed, and photographed with a digital camera. The images were analyzed using WinRHIZO 2012 software to determine the total length, diameter, total surface area, and volume of roots. Afterwards, the roots were taken to a drying oven and weighed to determine the dry mass. Overall, the results of this study indicate that multifunctional rhizobacteria provide greater initial root development in soybean, common bean, corn, and upland rice. Treatment with the isolate BRM 63524 resulted in greater total root length compared to the control treatment, standing out in the evaluated crops. Seedlings not inoculated with rhizobacteria tend to present lower root development than those inoculated.