The Wechsler Children Intelligence Scale–Fourth Edition (WISC-IV, 2005) allows to calculate the FSIQ and four index scores: verbal comprehension, perceptual reasoning, working memory, and processing speed. In 1998, Prifitera and colleagues recommended to calculate the General Ability Index (GAI), as an alternative composite score. This score is based on Verbal Comprehension and Perceptual Reasoning only. The objective of the first study presented in this paper is to provide the GAI normative tables for the French WISC-IV; these tables were created using a statistical approximation procedure. The objective of the second study is to test the validity of these tables with data obtained from 60 children. Correlation between FSIQ and GAI is 0.91 and the relative mean difference is only 0.18 point. These tables, for the French version of the WISC-IV, allow using the GAI as an alternative measure of general ability.