Recent investigations applying working memory training have indicated that it is possible to train intelligence. This work aimed to verify the effectiveness of a cognitive training program aimed at increasing children's intelligence. Fifty-three Brazilian children, enrolled in the sixth year of elementary school (M=11.17 years, SD=.37), were selected from a larger original group. This selected sample was randomly assigned into the experimental group/EG (n=27) and the control group/CG (n=26). All children were evaluated by cognitive measures in the pre-test and post-test phase. Three working memory tasks encompassed the cognitive training program. The cognitive training was administered to the EG twice a week for eight weeks. The post-test assessment was administered two weeks following the conclusion of the training program. The statistical analysis indicated no significant differences between EG and CG after training for cognitive measurements. These results demonstrate partial support of the selective literature that indicates the difficulty of achieving significant intellectual changes through specific intervention programs.