AIM. To test the hypothesis that overall intelligence quotient (IQ) is decreased in patients with Aarskog syndrome. METHODS. 21 boys under 17 years of age with a confirmed clinical diagnosis of Aarskog syndrome were assessed using the Griffiths mental development scales and the British ability scales. RESULTS. IQ ranged from 68 to 128 and followed a normal distribution. CONCLUSION. This study does not support the hypothesis that Aarskog syndrome is associated with a lowering of mean IQ.