Summary. Results are reported for mean IQs on the WAIS-R in Sudan in 1987 and 2007. There was a gain of 4·05 Full Scale IQ points over the 20-year period, representing a gain of 2·05 IQ points a decade. The Verbal IQ showed a loss of 1·65 IQ points, while the Performance IQ showed a gain of 7·2 IQ points. These results are broadly consistent with those in economically developed countries in showing that mean IQ on the WAIS-R has increased in Sudan, and the Performance IQ has increased more than the Verbal IQ.