The total neutron cross section of 242Pu has been measured from 0.0015 to 8000 eV, using PuO2 powder samples in the Materials Testing Reactor (MTR) fast chopper. The data give 26.9 ± 2.0 and 18.5 ± 2.0 b for the 0.0253 eV total and absorption cross sections, respectively. It was necessary to correct the total cross-section data for water contamination and for the effect of scattering by small particles. To determine the proper forms for these corrections, low-energy total cross-section measurements were made using samples of Al2O3 and ThO2. Analysis of resonances below 180 eV gives a resonance absorption integral of 1110 ± 60 b, and a neutron s-wave strength function of (0.99 ± 0.44) × 10−4. (A weighted average of data available on this isotope gives 1175 ± 70 b for the resonance absorption integral and 19.7 ± 1.0 b for the neutron absorption cross section at 0.0253 eV).