Background & Objective: Water resources are affected by different pollutants because of population growth, increasing water demand, and development of industries. A group of these pollutants are petroleum compounds which contain hazardous compounds such as BTEX. These compounds may cause undesirable health effects. Methods: In this study, activated carbon along with ozonation process was used for petroleum hydrocarbon removal from water samples. Samples were taken from groundwater resources located around Tehran Petroleum Refinery Plant. Activated carbon dosages were equal to 0.5, 3, and 5.5 g/l, and ozone flow was 2.5 l/min. Response surface methodology based on Box-Behnken was used to assess the effect of independent variables on the response function and prediction of the best response value. Analysis of variance (ANOVA) was applied for statistical analysis of the responses. Results: High value for R2 (0.98) shows that removal of COD can be described by this model. Although the value of R2 adjusted (0.96) was less than R2, however, it can be concluded that the model has fit the experimental data favorably. Conclusion: Use of an oxidant together with activated carbon can increases removal efficiency for organic compounds. In this study it was observed that efficiency of petroleum compounds' removal was greatly increased by addition of activated carbon as a catalyst with ozonation process.