In order to initiate appropriate programs for screening, early intervention, and meaningful psycho-educational programs, a children's community mental health center in Harlem, where over 95 percent of its clientele is black and/or Spanish speaking, requires, for all its referrals, an accurate assessment of intellectual strengths via an IQ battery. This investigation compared scores achieved by approximately 150 youngsters residing in East and Central Harlem on the Revised version of the Wechsler Intelligence Scale for Children (WISC) with scores achieved by a comparable population on the 1949 version of the WISC. Contrary to expectations, the revised version (supposedly standardized, unlike its predecessor, to reflect the 1970 census for the critical variables of race, occupational head of household, geographic region and the urban rural distribution) produced significantly lower scaled scores on several subtests which, in turn, significantly lowered full scale IQ scores. This fact seemingly penalized the very population which, it was indicated, was most likely to gain. Appropriate statistical measures were applied to determine the true significance of these results, taking into account sex and age of subjects. Implications for continued use of this new instrument were discussed and conclusions drawn. (Author/MV)