Skilled and unskilled readers from grades 3, 5, and 7 (9, 11, and 13 years of age, respectively) performed one of three memory tasks on a randomized list of primary word associates. One group rated each word as "good" or "bad" (incidental semantic task), another group produced a rhyming word for each list word (incidental rhyming task), and a third group attempted to memorize the list (intentional learning task). The recall results indicated equivalent recall for skilled and unskilled readers at all grades on the rhyming and intentional tasks; whereas, skilled readers were superior to unskilled readers on the semantic task. A clustering analysis produced a similar effect as skilled readers, who performed the semantic task, tended to cluster semantically-associated words together during recall more readily than unskilled readers. The results were construed as evidence for reading-skill differences in the semantic encoding of individual words. © 1978.