The effect of B2O3 addition on La2-xSrxCuO4 (LSCO) single-crystal growth by traveling solvent floating zone technique was examined. Experimentally, it was found that addition of boron oxide to the solvent provides a reduction of the solvent penetration into the feed rod and better seeding. No influence of boron on the superconductivity characteristics of grown LSCO single crystals was found. As a result high-quality, subgrain and inclusion-free La2-xSrxCuO4 single crystals with x = 0.0, 0.09 and 0.13 were prepared.