Acceptor-doped LaNbO4 has attracted considerable interest in applications for proton conducting fuel cells. The starting materials used for the conventional solid state reaction method (La2O3 and Nb2O5) have low reactivity, leading to difficulty in producing single phase LaNbO4. The present work reports the synthesis of La0.99Sr0.01NbO4-delta by a modified solid state reaction method using La(CO3)3 center dot xH(2)O, SrCO3 and C4H4NNbO9 center dot xH(2)O. Thermogravimetric analysis/Differential Scanning Calorimetry was used to study the decomposition of the starting materials. Powder samples were calcined at temperatures from 400 degrees C to 1100 degrees C and examined by X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FM). A calcination schedule of 1100 degrees C for 5 h was chosen. Samples could be sintered to 97% relative density at 1350 degrees C. XRD of sintered samples revealed the monoclinic phase of LaNbO4 and a La3NbO7 second phase. The electrical conductivity of the sample showed the activation energy of 0.9 eV, similar to that of the sample prepared by the conventional solid state reaction method. While the high frequency bulk conductivity is lower by a factor of ca. 3, the blocking effects due to the grain boundaries became weaker for the sample prepared by the modified solid state reaction method. (C) 2017 Elsevier B.V. All rights reserved.