[en] The neutron spectrum from a ²³⁸Pu-Li source has been measured using spherical proportional counters filled with different pressures of hydrogenous gas. The spectral shape over the energy range 60 keV-1.5 MeV is in good agreement with the calculated spectrum for a similar source and the neutron output obtained by integrating the spectrum is in good agreement with long-counter measurements. The neutrons from the ²³⁸Pu-Li source have an average energy of 0.50 MeV, an average kerma (in soft tissue) of 1.44 nrad . cm²/neutron and an average dose-equivalent index of 18.2 nrem . cm²/neutron. (author)