Case marking in English in available only on some pronouns and only in some cases. It is unknown whether young children acquiring English nevertheless make use of this highly restricted marking as a cue to sentence interpretation. The current study therefore examined how 2- and 3-year-old English children use case-marked pronoun frames and constructional word order cues (actives versus passives) to understand agent-patient relations in transitive sentences containing novel verbs. In a pointing comprehension test, 2-year-olds used pronoun frames containing two case-marked pronouns to help them interpret grammatical sentences, both actives and passives, but they were unable to assign agent patient relationships in any consistent way with ungrammatical pronoun frames. Threeyear- olds also used pronoun frames to interpret grammatical active and passive sentences (with either one or two case-marked pronouns) but varied in their interpretation of ungrammatical sentences according to pronoun frame. These results suggest that the role of case-marked pronouns has been underestimated in English language acquisition, and that even very young English children use multiple cues to comprehend transitive sentences. © Taylor & Francis Group, LLC.