Objective: This study examines the effectiveness of the traditional teaching and deductive thinking skills teaching methods on academic achievement in students with intellectual disabilities. Method: A pretest-posttest control group design was chosen for study and follow up data was gathered. The sample consisted of 54 male and female students with intellectual disabilities in 4^th and 5^th grades of exceptional elementary school in Hamedan. This sample was divided into two groups of experimental and control, and treatment was assigned randomly to one of this groups. Analysis of data was accomplished by Covariance test. Results: Data analyses indicated that training by deductive thinking skills method was significantly more effective. Conclusion: Accordingly, we can suggest that teaching deductive thinking skills to students with intellectual disabilities can be a helpful teaching method.