The velocity of sound in helium was measured to be 972.49±0.11 m/sec. The measurements were made using a resonance tube method at standard pressure and at 0°C. The tube, unique because of rigid plates at both ends, with acoustic coupling through small holes in one plate, is described. Corrections are made for the sound speed decrease caused by viscothermal absorption at the tube walls. A detailed description of the methods used in making the measurements is included, and the possible sources of errors are discussed.