Six large river systems occur in Arkansas; from longest to shortest, they are the White, Ouachita, Mississippi, Arkansas, Saint Francis, and Red rivers. These, along with their numerous tributaries, 250,000 ha of lakes and reservoirs, and 32,000 km of streams, support [greater than or equal to] 216 species of fishes (Robison and Buchanan, 1988). In recent years, little has been published on the fish fauna occurring in large rivers of the state. Indeed, large rivers in Arkansas have been relatively under sampled and continual human-induced changes in these systems are a cause for concern for native fishes. Buchanan et al. (2003) reported on fishes of the Red River, a turbid 217-km-long plains stream that drains southwestern Arkansas. In addition, McAllister et al. (2009b) reported distributional records for three species of Notropis from the Arkansas, Black, Mississippi, and White rivers. We conducted an intensive 3-year fish survey of the six largest rivers (and two of their large tributaries) in Arkansas during March 2006-October 2008. We sampled 40 reaches distributed among 8 rivers, including the Little (1 reach), Red (2), Arkansas (3), Ouachita (4), Saint Francis (6), Black (6), White (6), and Mississippi (12) rivers. We used hoop nets (ca. 1.2 m in diameter, 3.8-cm bar mesh, ,14 hoop-net nights/reach), mini-fyke nets (ca. 1.2-m wide by 0.8-m deep, 3.8-cm bar mesh) along shorelines in a variety of habitats, and seines (1.8 by 12.2 m, 6.4-mm mesh, 10 hauls) to sample areas that were relatively free of debris. We used small trawls (ca. 7 hauls) similar to Herzog et al. (2005) to sample open-water habitats whenever possible. We made trawls reasonably close and parallel to shorelines and, when possible, in the adjacent channel. In a few instances, trawls were virtually impossible due to debris (tree limbs). At each locale, we recorded depth of water, substrate, velocity (m/s), temperature of water, turbidity (Secchi disk, m), GPS coordinates, and habitat descriptors. We examined and classified substrates directly or in combination by dragging a chain from a boat and observing vibration in deeper waters.