This study looks at the relationship between L1 (Russian) attrition and L1 reading ability in Russian-English-speaking bilingual children. Ten Russian-English bilingual children and 10 adults participated in this study. Nine out of 10 children participants were born in the US and used L1 as their primary language of interaction within the family, but the intensity and the length of uninterrupted L1 exposure differed for each child. All participants were tested on perception (grammaticality judgement) and production (narrative) tasks to assess their sensitivity to and retention of the morphosyntactic structure of L1. All children showed some attrition of grammatical morphemes, specifically in the Russian systems of declension and conjugation; however, the degree of attrition correlated with reading ability in L1, i.e. children with L1 reading skills showed a lesser degree of attrition for some language-specific morphosyntactic structures. This finding shows interdependence of oral and reading skills and points to the role reading in language with shallow orthography may play in preservation of L1 grammatical structures in oral language. The implications for the clinical applications are also discussed. (Contains 2 tables and 4 figures.)