An experiment examined the role of word order and case inflection in the interpretation of Czech transitive sentences by children and adults. Participants listened to simple transitive sentences while watching picture pairs with the same characters performing the same action, but with the opposite assignment of the subject and object roles. Sentences varied in word order (SVO, OVS), and in whether the initial noun was case-ambiguous or not. Word order and case inflection appear to have only weak, if any, immediate influence on 3-year-olds sentence interpretation. The performance in 5-year-olds revealed sensitivity to both word order and inflection, similar to the performance of adults. However, 5-year-olds appear to be driven by word order more than adults. Surprisingly, processing of OVS sentences in adults was not different from SVO sentences as long as the initial noun was unambiguously inflected for case. The results are discussed from the viewpoint of the competition model, and a processing basis for some of the children's deficits is proposed.