A new photogrammetric technique has been developed for monitoring the morphology of evolving stream beds. A pair of commercial cameras is used to record the evolution of the bed, and a computational approach that consists of a set of computer-vision and image-processing algorithms is employed to analyze the videos and reconstruct the instantaneous 3-D surface of the bed. Time-and space-resolved measurements are obtained to generate accurate representations of the bed. The required setup for the implementation of the technique is relatively simple and minimally intrusive. A thorough description of the algorithms that were used and detailed instructions for the implementation of the technique is provided. High-resolution measurements of a gravel bed in a clear-water, bridge scour experiment were carried out to demonstrate the operation and validate the capabilities of the technique. The new technique shows advantages compared to existing methods in terms of spatial resolution, temporal resolution, simplicity, and cost. Citation: Bouratsis, P., P. Diplas, C. L. Dancey, and N. Apsilidis (2013), High-resolution 3-D monitoring of evolving sediment beds, Water Resour. Res., 49, doi: 10.1002/wrcr.20110.