Abstract: An improved hydro-turbine having a casing with an inlet port and an outlet port. A driveshaft is journaled in the casing and a rotor is secured to the driveshaft. The rotor has a cylindrical member whose radius is at least greater than 50 percent of the radius of the peripheral wall casing. A plurality of vane members extend outwardly from the outer radial surface of the cylindrical member. The vanes are spaced around the perimeter of the cylindrical member and each vane has a front surface and a rear surface. The front surface is substantially flat and the rear surface is convex in cross-section. The bottom edge of the rear of each vane is located substantially adjacent the bottom edge of the front surface of the adjacent vane member. The vane members extend substantially across the entire width of the cylindrical member.