Abstarct: Pollution caused by crude oil and its derivatives is the most prevalent problem throughout the world, during its crude oil extraction, transport, refining and burning. Oil spills can have serious effects on humans and other creatures. Therefore cleaning up environmental oil pollution is an alternative technique for physicochemical methods. The purpose of this study was to evaluate the biodegradation rate of fuel-oil contaminated soil by alfalfa (Medicago scutellata) and grass (Poa bulbosa) along with Pseudomonas putida bacterium. Thus, alfalfa and grass seeds were planted in two density levels with and without Pseudomonas putida in pots containing fuel oil-contaminated soil under greenhouse condition. Soil samplings were done in germination, vegetative and reproductive's stages of plant's growth. Results obtained in this study showed that both alfalfa and grass plants decreased fuel oil in the contaminated soil. The treatment of bacteria and the plants with high density had a positive effect in reducing the amount of soil's hydrocarbon contamination. However, this reduction was not significant than treatments without bacteria and plants with less density. Also, petroleum hydrocarbon contaminated soil to reduce growth and germination of both species.