The purpose of this study was to examine the relation between the ability to quickly acquire initial mental graphemic representations (MGRs) in kindergarten and fourth grade literacy skills in children with typical language (TL) and children with language impairment (LI). The study is a longitudinal extension of a study conducted by Wolter and Apel in which kindergarten children with LI and TL were administered early literacy measures as well as a novel written pseudoword task of MGR learning (spelling and identification of target pseudowords). In the current study (4 years later), the authors administered reading and spelling measures to 37 of the original 45 children (18 children with LI, 19 children with TL). The children with LI performed significantly lower than their peers with TL on all fourth grade literacy measures. For both groups, kindergarten initial MGR acquisition ability significantly related to fourth grade real-word reading and spelling. For the children with LI, kindergarten initial MGR acquisition ability also related to fourth grade pseudoword decoding and reading comprehension. Collectively, the findings suggest that initial MGR learning in kindergarten is an essential skill that may uniquely relate to later literacy abilities. (Contains 3 tables and 1 note.)