This article presents a selective review of previous research findings on first language (L1) attrition. The review is intentionally limited in scope as it only discusses studies on morphosyntactic attrition in the L1 grammar of adult bilinguals. To this end--and in order to present the most current line of research in this field--I first report on studies that appeared in three recent collections of papers on L1 change or attrition. I then discuss findings reported in these three volumes as well as those reported elsewhere, in order to identify morphosyntactic features that are more vulnerable to change due to L2 interference.