An investigation has been performed of hydrodynamic losses through filter screens used in power plant water intakes. For the experimental phase of the investigation, screens with aspect ratio up to 3.8 were tested. The Reynolds number range for the test was from 15-1 and the ratio of traveling screen velocity to water approach velocity varied from -1.. It was found that the characteristics of flow through slot mesh screens are similar to those for flow through square mesh screens. The losses through round wire screens can be estimated from the approach water velocity, wire diameter, and a function of the ratio of opening area to frontal area of the screen. If a finer screen mesh is desired for filtering purposes, slot mesh screens sustain smaller hydrodynamic losses than square mesh screens because the ratio of openings is larger. It was also found that the screen motion in the water could be easily simulated. It was determined that the losses for a traveling screen are the same as those for a stationary screen of the same design so long as the normal component of the approach velocity remains unchanged.