Alpha-particle losses due to pitch-angle scattering into the loss cone of an open-field-line configuration are investigated. Specifically, the particle loss and the corresponding energy loss are given as explicit functions of energy during slowing-down. It is found that the alpha-particle energy loss due to pitch-angle scattering for a pure DT-plasma is of the order of 5–10%, in contrast to the 35–40% obtained in a recent paper