The results obtained show that the chitosan microspheres used as natural polymeric resins perform well in removing heavy oil from produced water, with adsorption efficiency greater than 90% in the beginning of the test, ie, over than 180 ppm of these oil was removed from oily water for both flow used. During the test the flow reduction had great influence on efficiency, having the lowest flow a volume of treated water much higher. Considering that the concentration of the incoming water was about 200ppm of oil, and that the outlet was below the limits set by CONAMA, which is 29 ppm, it is material present high capacity for this application. Besides this, the microspheres had good resistance, maintaining their spherical shape despite the pressure applied on them in the elution column.