The electrical resistivity and tensile properties of copper and oxide dispersion strengthened (DS) copper alloys have been measured before and after fission neutron irradiation to damage levels of 0.5 to 5 displacements per atom (dpa) at ~ 100 to 400 o C. Some of the specimens were irradiated inside a 1.5 mm Cd shroud in order to reduce the thermal neutron flux. The electrical resistivity data could be separated into two components, a solid transmutation component Δρ t r which was proportional to thermal neutron fluence and a radiation defect component Δρ r d which was independent of displacement dose. The saturation value for Δρ r d was ~ 1.2 nΩ m for pure copper and ~ 1.6 nΩ m for the DS copper alloys irradiated at 100 o C in positions with a fast-to-thermal neutron flux ratio of 5. Considerable radiation hardening was observed in all specimens at irradiation temperatures below 200 o C. The yield strength was relatively insensitive to neutron spectrum in specimens strengthened by dispersoids or cold-working.