Crude oil effects were examined on Robinia peseudoacacia L. leaf flavonoids. Ten R. peseudoacacia seeds cultivated in 4 treatments: 0% (control), 1%, 2% and 3% crude oil in three repetitions in equal condition for 12 weeks. Leaf flavonoids examined using chromatographical methods. Results showed phytochemical changes in crude oil grown plants. Those were amount and number changes and appearance leaf flavonoids in comparison with control. This study showed flavonoids may have a protective defensive role against some environmental stresses such as crude oil pollutants and plants must have mechanisms that make them resistant to adverse environments and retain their fitness. Keywords: Crude Oil, Flavonoids, Robinia Peseudoacacia L
