As a subset of genetic abnormalities, subtelomeric deletions have been found in 7-10% of individuals with mental retardation (MR). One subtelomeric deletion, Wolf-Hirschhorn syndrome (WHS), causes mild to severe MR, but the cognitive-behavioral features of individuals with WHS have not been studied systematically. To that end, we administered a comprehensive cognitive-behavioral battery to 12 children with WHS, ages 4-17 years, who also had some expressive language. Using the Stanford-Binet (4th Edition), we found cognitive deficits ranged from mild to severe, with mean IQ = 44.1. Interviewing parents with the Vineland Adaptive Behavior Scales, we found mean adaptive behavior score (DQ) = 37.3, with females exhibiting slightly higher scores than males. Cognitive profiles indicated relative strengths in Verbal and Quantitative Reasoning. Adaptive behavior profiles noted significant relative strengths in the Socialization Domain. These cognitive-behavioral profiles differed from children with other subtelomeric deletion syndromes, 2q37 or 8p23. Attention deficits and hyperactivity (ADHD) were observed in 7/12 (58%) of the children we tested. One child attained a score on the Child Autism Rating Scale (CARS) suggestive of mild autism. We conclude that different genetic disorders, which cause MR, produce diverse cognitive-behavioral profiles. Consequently, cognitive-behavioral profiles of children with MR need to be assessed more comprehensively.