The structural and dielectric properties of bulk (1-x) BaTiO3- x BiScO3 (x = 0 - 0.6) ceramics were investigated to acquire a better understanding of the binary system, including determination of the phase diagram, dielectric properties, and the difference in roles of Bi and BiScO 3 doping on BaTiO3. The solubility limit for BiScO 3 into the BaTiO3 perovskite structure was determined to be about x = 0.4, which was much higher than the solubility of Bi alone. A structural change from tetragonal to pseudocubic was observed at about x = 0.05 - 0.1 at room temperature. Dielectric measurements revealed the gradual change from typical ferroelectric behavior in pure BaTiO3 to a highly diffusive and dispersive relaxor behavior from 10 to 40 mol% BiScO3. Several of the compositions showed high permittivities (approximately 1000) with low temperature coefficients of capacitance.