The quasi-one-dimensional hexagonal perovskites BaVS3 and BaVSe3 are susceptible to doping under high pressure. At 3 GPa, 900 degrees C, barium was replaced with potassium, and mixed chalcogenides BaV(Se,S)(3) were stabilized. X-ray powder diffraction revealed that the product from the high-pressure synthesis was dominated by strain. The potassium-rich samples swiftly absorbed water in humid air. Rietveld analysis and assumption of Vegard＇s law indicated that selenium can replace sulfur in all ratios, whereas potassium only partially replaces barium. In this paper, the synthesis and Rietveld refinement results for the sulfides are reported.