Radial profiles of the ion temperature have been measured on PLT by using neutron flux Doppler broadening of oxygen, carbon and helium line radiations, and charge exchange. The ion temperature (⪅ 1.2 keV) is consistent with Hinton-Rosenbluth neoclassical heat conduction in the plateau regime as the dominant energy loss from the plasma with central ion energy confinement times ⪅ 0.1 s.