The electron dephasing processes in two-dimensional homogeneous and inhomogeneous indium tin oxide thin films have been investigated in a wide temperature range 0.3-90 K. We found that the small-energy-transfer electron-electron (e-e) scattering process dominated the dephasing from a few K to several tens K. At higher temperatures, a crossover to the large-energy-transfer ee scattering process was observed. Below about 1-2 K, the dephasing time τϕ revealed a very weak temperature dependence, which intriguingly scaled approximately with the inverse of the electron diffusion constant D, i.e., τϕ(T ≈ 0.3 K) ∝ 1/D. Theoretical implications of our results are discussed. The reason why the electron-phonon relaxation rate is negligibly weak in this lowcarrier-concentration material is presented.