Since the recent work of the Westar Institute's Acts Seminar, and especially the publication of Richard Pervo's Dating Acts, the possibility that Paul's letters served as a source for the book of Acts requires renewed examination. This article tests the hypothesis of Luke's dependence on the Pauline corpus by examining its credibility as an explanation for one particular feature of the narrative, namely, Paul's itinerary as reported in Acts 15:36–20:16. The basic geographical framework of these chapters is easily explicable as Lukan deduction from Paul's letters; differences in detail are convincingly explained as Lukan redaction, clearly in keeping with his theological and narrative interests and in accord with the editorial procedure that is evident, mutatis mutandis, in his Gospel. What is more, this hypothesis accounts for features of the narrative that other theories of the itinerary's source do not, specifically, the remarkable correspondence between those cities named in the Pauline corpus and those that serve as Luke's narrative settings for Paul's activity, as well as the intertextual resonances in Acts 19:21 and 20:22 of Paul's travel announcement in Rom 15:31. In short, an examination of Paul's itinerary in these chapters provides strong confirmation of the explanatory value of the hypothesis that Luke used Paul's letters as a primary source.