A process for dewatering hydrocyanic acid by distillation, which includes distilling crude hydrocyanic acid containing from 50 to 99.9% by weight of HCN, from 0.1 to 40% by weight of water, from 0 to 15% by weight of carbon oxides and optionally from 0.01 to 1% by weight of an involatile stabilizer, at a pressure of from 1 bar to 2.5 bar, a bottom temperature of from 100.degree. C. to 130.degree. C. and a top temperature of from 25.degree. C. to 54.degree. C., in the absence of a volatile stabilizer, in a distillation column to obtain a top draw stream containing purified, anhydrous hydrocyanic acid and carbon oxides and a bottom draw stream including water and, optionally, the involatile stabilizer.