Purpose: This study investigated prosodic boundary effects on the comprehension of attachment ambiguities in children with cochlear implants (CIs) and normal hearing (NH) and tested the absolute boundary hypothesis and the relative boundary hypothesis. Processing speed was also investigated. Method: Fifteen children with NH and 13 children with CIs (ages 8-12 years) who are monolingual speakers of Brazilian Portuguese participated in a computerized comprehension task with sentences containing prepositional phrase attachment ambiguity and manipulations of prosodic boundaries. Results: Children with NH and children with CIs differed in how they used prosodic forms to disambiguate sentences. Children in both groups provided responses consistent with half of the predictions of the relative boundary hypothesis. The absolute boundary hypothesis did not characterize the syntactic disambiguation of children with CIs. Processing speed was similar in both groups. Conclusions: Children with CIs do not use prosodic information to disambiguate sentences or to facilitate comprehension of unambiguous sentences similarly to children with NH. The results suggest that cross-linguistic differences may interact with syntactic disambiguation. Prosodic contrasts that affect sentence comprehension need to be addressed directly in intervention with children with CIs.