The authors describe the neurocognitive and behavioral phenotype of 16 South African children (ages 4-16 years) with Duchenne muscular dystrophy, compared with 13 controls. The preschool group performed significantly worse than the controls in measures of general developmental performance. The school-age group showed no significant differences in general intellectual abilities. However, our data identified that boys with Duchenne muscular dystrophy experience mild cognitive dysfunction across multiple domains, including visual memory, and verbal and nonverbal executive functioning. Parental reports of 11 boys with the disorder revealed high rates of general behavioral problems (54.5%). The cognitive profile of boys with Duchenne muscular dystrophy in South Africa is similar to that described elsewhere in the world. Behavioral problems in our cohort were higher than previously reported. This may be partially explained by the poor socioeconomic background of the majority of the cohort.