La2Mo2 − xWxO9 (x=0, 0.5, 1.0, and 1.3) nanocrystalline powders were synthesized by spray pyrolysis (SP) assisted by an ultrasonic atomizer. Microstructure, sinterability and thermal stability of the prepared powders were investigated. Spherical particles of 430 to 530 nm in diameter and crystallite sizes in the 30–44 nm range were obtained. Additionally, the fine microstructure has allowed the reduction of sintering temperatures with respect to that usually reported for a solid-state reaction (SSR) method. Pellets with a variety of average grain sizes and morphologies were obtained by applying different sintering programs starting from La2Mo2 − xWxO9 powders (x=0 and 1.3) obtained by SP and SSR processes. The electrical properties of these ionic conductors were analyzed by Electrochemical Impedance Spectroscopy (EIS) and correlated with microstructural observations. No significant variation of the electrical properties of these ionic conductors was found as compared to conventional ceramics with remarkable microstructural differences.