Objective: The present study investigated the performance of Brazilian children in the Continuous Performance Test, CPT-II, and compared results to those of the norms obtained in the United States. Method: The U.S. norms were compared to those of a Brazilian sample composed of 6- to 11-year-olds separated into 4 age-groups (half boys) that represented the socioeconomic class distribution of Sao Paulo City. The children were prescreened for attention deficit disorders (ADHD). Results: Age and gender effects in the Brazilian sample were similar to those previously described. However, the Brazilian sample showed better performance in almost all measures in all age-groups compared to that of the United States. Conclusion: It is discussed that differences between samples probably reflect lack of ADHD screening of the U.S. children. More studies are necessary to determine if the CPT-II is a cross-cultural test with participants from different samples matched for age, gender, and socioeconomic status screened for ADHD. (Contains 7 tables.)