Although sentences are thought to be generally easier to process when given information precedes new information, closer examination reveals that these preferences only manifest within some syntactic structures. Here, we examine the consequences of the relative ordering of given and new information ("information structure") for the on-line comprehension of prepositional-object (PO) and double-object (DO) dative sentences. Experiment 1 demonstrated using self-paced reading that the on-line comprehension of DO structures, but not PO structures, is more difficult with new-before-given information structure. Experiment 2 assessed the comprehension of dative sentences with animate themes to evaluate two potential sources of this interaction: information-structural constraints encoded within syntactic representations ("argument structure hypothesis") vs. word-to-word contingency statistics ("linear position hypothesis"). Despite experiment-wise differences in word-to-word contingency statistics, the interaction between syntactic structure and information structure persisted in Experiment 2. Taken together, these results suggest that syntactic representations can include information-structural constraints on their arguments. (Contains 2 figures and 6 tables.)