This dissertation intends to verify whether syntactic impairment, as detected in in the oral comprehension of costly structures - object WH plus N questions (OWH plus N) and object relative clauses (ORCs) -, predicts difficulties in reading fluency and comprehension. The syntactic abilities of 6th graders from three public schools in Rio de Janeiro were evaluated, giving rise to syntactically impaired (SI) and control (CT) groups. Those who satisfied criteria at the word level in word-recognition/reading tasks proceeded. Two experiments assessed reading fluency (rate, accuracy, prosody) and the comprehension of each of the target structures in isolation (picture-identification task) and in discourse (self-paced reading task). In the latter, the intervening subject was manipulated for structural complexity (full nominal phrase and pronoun). One aspect of prosody (pitch contour) distinguished the groups, with lower scores in the SI group in both tasks. An aspect of accuracy (number of disfluencies) distinguished them in the discourse task (more disfluencies in the SI group). The comprehension of the target-sentences is isolation was harder for the SI group. Lexical/discourse factors can create differential demands for sentences in discourse, minimizing group effects. The effect of intervention was in the predicted direction for OWH plus N sentences (more demands for full nominal phase subjects). As for RC, this effect was not significant, possibly due to difficulties in the ascription of illocutionary force to YES/NO questions. In an overall analysis of reading fluency in discourse (different structures/punctuation marks), the pitch contour indicates syntactic impairment. Impairment at the syntax-prosody interface can account for these results.