The problem of determining neutron yield from the (α, n) reaction has been the subject of much investigation, mainly experimental, for a number of years. Calculated values depend on cross sections and other nuclear data, which are not available for all isotopes. As a compromise, using the experimental data as a basis, an expression has been derived to provide a simple computation of the neutron yield in any given mixture containing actinides. This has been successfully tested with known (α,n) neutron source strengths in compounds of plutonium.