Percina macrolepida has previously been reported from 5 localities in the western portion of the Arkansas River basin in Colorado, New Mexico, and Oklahoma, presumably as a result of introductions. Examination of museum specimens and field sampling in 2000–2001 revealed that P. macrolepida is more widely distributed in the Arkansas River drainage than previously known. We documented the first records of P. macrolepida from the Arkansas River in Arkansas, where it occurs in large numbers throughout the McClellan-Kerr Arkansas River Navigation System. In the Arkansas portion of the Arkansas River, P. macrolepida occurred only in habitats in the main channel, often at the same localities as the morphologically similar P. caprodes. Percina caprodes was the only logperch species found in Arkansas River tributaries or reservoirs on tributaries in Arkansas. Arkansas River basin records for P. macrolepida in Oklahoma are currently known only from the Canadian River drainage, but additional sampling from the Arkansas River main channel in that state could produce new records for this species. It might not be possible to determine whether P. macrolepida is native or introduced in the Arkansas River basin, but it has likely increased in numbers in the Arkansas River in recent decades as a result of the construction of the navigation system.