Abstract: In a snow plow having a horizontally elongated blade that extends lengthwise obliquely to the direction of plow travel, a snow retaining gate is mounted in front of the plow blade to swing flatwise about a horizontal axis near the top of the plow blade and substantially parallel to the direction of plow travel. When raised, the gate wall is substantially horizontal but has downwardly concave curvature from rear to front for close fit of its rear portion under the forwardly-upwardly curved upper portion of the plow blade. The rear edge of the gate wall has a curved upper portion so that when the gate wall is in lowered substantially upright position its rear edge, along the full height thereof, is contiguous to the front surface of the plow blade. When in lowered position the gate wall is oriented substantially parallel to the direction of plow travel and thus prevents formation of a secondary snow bank.