A rapid, alternating stimulus (RAS) naming measure was designed to study the developing ability in dyslexic readers to direct attention to contextual patterns while performing a rapid serial naming task. The results from a 3-year longitudinal investigation of 98 children indicate three trends. RAS performances differentiate both average from impaired readers and dyslexic subgroups from each other. The largest, most impaired subgroup can not complete the RAS tasks in kindergarten; the smaller subgroups have little name access speed deficits. Early RAS performances are highly predictive of later reading, particularly at the single-word reading level. Implications for understanding the development of automaticity and the relationship between retrieval speed and reading are discussed.