The purpose of this study was to investigate the use of Korean case particles in a Korean-English bilingual child with specific language impairment (SLI). The child's production of four types of Korean case particles were compared to those of three typically developing children during probe and storytelling tasks. The Korean-English bilingual child with SLI produced the vocative and the nominative for person case particles similar to children matched on age and mean length of utterance (MLU). He produced the nominative for object and accusative case particles similar to the MLU-matched child but exhibited lower performance than that of his age-matched peers. The results suggest that longer duration of Korean case particles in the phrase-final position may provide perceptual salience and not pose particular difficulty for the Korean-English bilingual with SLI. Frequent omission of the accusative by the child with SLI and his MLU-matched peer, however, supports the argument that frequency effect in linguistic input influences morphological development. (Contains 6 tables and 1 figure.)