Aims: The purpose of this research was to investigate the effects of plant growth-promoting rhizobacteria and the cold stratification periods on seed germination of Vaccinium arctostaphylos. 
Material & Methods: The seeds were inoculated with growth-promoting bacteria, including Bacillus subtilis, Enterobacter cloacae, and Pseudomonas putida, as well as a combination (co–inoculation) of all strains. Then, they were subjected to cold stratification in a refrigerator at 4±1°C for 0, 1, 2, 3, 4, and 5 months. At the end of each period, seeds were sown in polyethylene bags (15 cm × 8 cm) containing cocopeat, perlite, and sand (1:1:2) and placed in a greenhouse with temperatures of 22°C and 25°C and relative humidity of 60% and 70%, respectively. After 40 days, germination percentage, germination speed, and seed vigor index (SVI) were calculated.
Findings: Results indicated that bacterial inoculation and their interactions influenced germination traits. Germination percentage ranged from 0 to 58.50%. Both inoculation and CS positively affected germination percentage. The highest seed germination rates (57.50-58.50%) and germination speed (2.26 n. d-1) were observed in co-inoculated seeds with all bacteria combined and 4 to 5 months of cold stratification, respectively. The maximum shoot length (23.25 mm), root length (17.98 mm), and seed vigor index (24.12) were recorded for co-inoculated seeds with all bacterial inoculants and 5 months of cold stratification. 
Conclusion: The results confirmed overcoming seed dormancy, increased seed germination components, and early seedling growth in V. arctostaphylos. Plant growth-promoting rhizobacteria are more effective when combined with cold stratification.