Flash-sintering is a promising approach for the ultra-rapid densification of ceramics at low furnace temperatures under an applied electric field. Here we have studied the effect of atmosphere on the flash-sintering of titania (TiO2) nanopowders under an applied electric field of 400 V.cm−1, and find a dramatic reduction in the flash-onset furnace temperature (TF), from 648°C in air to 239°C in argon (Ar). The reduced TF is close to the TiO2 Debye-temperature limit. This is attributed to a combination of nanocrystalline nature of the TiO2 powder and the O2-lean Ar atmosphere, resulting in enhanced electrical-conductivity characteristics. The reduced TF also results in finer, uniform average grain sizes (360 nm to 190 nm) and lower, uniform porosity (0.5% to 1.4%), going from the anode to the cathode. In contrast, in air the corresponding average-grain-size range is 9.6 μm to 1.3 μm and the porosity range is 1.9% to 3.3%.