Extracting and transporting a significant amount of oil and gas from the Persian Gulf have brought devastating damages to marine environment due to oil spills and water pollution. The oil spill in water brings damages to the ecosystem, coastline businesses and human health; particularly to fishery and tourism activities. Hence, it is a crucial task to model oil spill damages and evaluate risks. By identifying the oil slick behaviour and considering the velocity and cleaning capacity of oil cleaning vessels, the genetic algorithm (GA) was used to obtain the optimum placement of the vessels for several oil spill scenarios. Meanwhile, six major risks of damages were identified for the Persian Gulf in terms of marine ecosystem, tourism, fisheries, beach entry bans, commercial and transit ports closures. All these factors were systematically analyzed using analytic hierarchy process (AHP). AHP provided a quantitative analysis of probabilities of hazards, financial losses and environmental damages. Based on location, volume of oil spill, weather condition and optimum placement of oil cleaning vessels, the risk map of oil spill in the Persian Gulf was developed and the effects of each major risk and overall risks were assessed.