This study reports the results of a componential analysis of items comprising Sections A and C of Form Z of the reading comprehension portions of the California Achievement Tests (CAT) (Tiegs & Clark, 1963). A set of problem components or attributes characterizing the test items in terms of manifest content, psychologically salient features, and processing demands was developed, including methods for their quantification. The contributions of these components to task difficulty were then evaluated using linear regression methodology. Item difficulty indices were transformations of the familiar proportion-correct item score, obtained from data gathered during the spring of 1989 from 158 deaf examinees. Variation in the item difficulty values was substantially accounted for in terms of a small number of predictor variables (R2 greater than or equal to .90). Implications of the results for construct validity and interpretation of test scores are discussed.