Various recent studies attest that reading involves creating an implicit prosodic representation of the written text which may systematically affect the resolution of syntactic ambiguities in sentence comprehension. Research up to now suggests that implicit prosody itself depends on a partial syntactic analysis of the text, raising the question of whether implicit prosody contributes to the parsing process, or whether it merely interprets the syntactic analysis. The present reading experiments examine the influence of stress-based linguistic rhythm on the resolution of local lexical-syntactic ambiguities in German. Both speech production data from unprepared oral reading and eye-tracking results from silent reading demonstrate that readers favor syntactic analyses that allow for a prosodic representation in which stressed and unstressed syllables alternate rhythmically. The findings contribute evidence confirming immediate and guiding effects of linguistic rhythm on the earliest stages of syntactic parsing in reading. (Contains 5 figures and 9 tables.)