Solid solutions of (1 - x)BaTiO3-xK(0.5)Bi(0.5)TiO(3) were prepared by the solid state reaction technique. Samples were sintered in reducing atmosphere of N-2/H-2 in the temperature range 1100-1240 degrees C with subsequent oxidation at 700 degrees C. Phase composition and crystal structure were investigated by X-ray powder diffractometry (XRPD). It was shown that all samples of (1 - x)BaTiO3-xK(0.5)Bi(0.5)TiO(3) (0 <= x < 0.4) exhibit a tetragonal structure at room temperature, the parameters a and c decrease with increasing x. With increasing x the Curie temperature of solid solutions (1 - x)BaTiO3-xK(0.5)Bi(0.5)TiO(3) (0.1 <= x < 0.4) increases from 150 to 220 degrees C. The values of potential barriers at grain boundaries were calculated on the basis of Heywang model. With increasing x, the potential barrier at grain boundaries increases. It was shown that the grain size decreases with increasing the bismuth potassium titanate content. The complex impedance results indicate that the grain boundary and the outer layer region, located between the boundary and the core of the grain, make a contribution to the positive temperature coefficient of resistance (PTCR) effect in (1 - x)BaTiO3-xK(0.5)Bi(0.5)TiO(3) solid solutions. With increasing x p(max) increases due to an increase in potential barrier at grain boundaries. (c) 2012 Elsevier B.V. All rights reserved.