Abstract—The purpose of the study was to look into the microbes responsible for the deterioration of onion bulbs near Vadodara. Sample was obtained from a neighbourhood market. Analyses were conducted using culture characterisation, Gram staining, and biochemical test. Staphylococcus sp, Bacillus sp, Pseudomonas sp, Klebsiella, and Escherichia coli were the bacteria species that were isolated, whereas Aspergillus sp, Mucor were the fungi. New, appropriate pre-harvest and post-harvest disinfection techniques must be developed. From this study conclusion is that spoiled onion bulbs are a source of both bacterial and fungal organisms that are known to induce spoiling. It may also be the result of the onions being exposed to unfavourable conditions during transportation, storage, and inadequate packaging, which could raise the temperature and humidity of the product. Several of the isolated organisms were amoxicillin-resistant yet susceptible to streptomycin, chloramphenicol, and other antibiotics.