Compositions with x≤0.10 have been synthesized in the system BaSn1-xNbxO3 by the solid state ceramic method. All the compositions have been found to be single phase solid solution having cubic structure. Lattice parameter for all the compositions remains almost the same. The optical micrographs show that average grain size is ≪1 μm. Dielectric constant and dielectric loss have been measured as a function of frequency (100 Hz–10 MHz) and temperature (300–500 K). Space charge polarization and orientational polarization contribute to the observed dielectric behavior.