In this letter, collisionless α-particle losses in tokamak reactors are studied. Orbit losses of high-energy α-particles are calculated. The results are presented in a parameterized form which allows the fraction of α-particles lost and the load on the first wall in tokamaks of practical interest, circular and both with elliptical cross-sections, to be determined. The possibility of α-particle losses due to the excitation of various types of thermonuclear instabilities in the plasma is also examined.