A study consisting of three components is reported. During Phase One an extensive literature search led to a compiled set of norms for reflexive and voluntary prehensile development. Phase Two included the clinical use and revision of the resultant Erhardt Developmental Prehension Assessment (EDPA©). Phase Three involved the testing of the EDPA for interrater reliability, which resulted in highly significant intraclass correlations. Single test item correlations were also analyzed to identify items needing clarification or alteration in preparation for final revision of the instrument. A sample application in the clinical field is illustrated by segments of an EDPA used to develop an Individualized Educational Plan, required by Federal Law 94-142 (Education of All Handicapped Children).