This study was designed to explore the effects of linguistic prosody on the processing of "filler-gap" sentences. We designed two experiments to determine first whether the sentence processor uses information contained in the prosodic contour of an utterance during on-line processing, and second the form that information may take. In Experiment 1, we found that prosody apparently influences when listeners posit gaps on-line. In Experiment 2, we obtained acoustic evidence that gaps are represented in the prosodic contour of an utterance. The results of this study support a view in which prosody contributes very early to on-line structure building mechanisms during sentence processing.