We investigated the relationship between swimming performance of the leopard darter Percina pantherina evaluated in the laboratory and current velocities measured at the ends of corrugated-pipe and open-box culverts through road crossings. We tested leopard darters at each of six current velocities ranging from 0 to 60 cm/s and measured burst frequency and distance. We used analysis of variance (ANOVA) to analyze burst frequency and total distance covered during a 10-min period and found that at a current velocity of 25 cm/s, fish swam more frequently and for greater total distances than at higher or lower velocities. When a nested ANOVA was used to remove variation due to individual fish, we found that distances of individual bursts also differed significantly and that fish in intermediate velocities had longer bursts. Current velocities in box and pipe culverts tended to be higher than the velocities measured in the lab, and several crossings had structural barriers, in addition to high current velocities. Although there is no evidence that culverts act as long-term barriers to migration or dispersal of leopard darters, they may prevent migratory activity during certain years, thereby negatively affecting localized populations.