Large-size inclusion-free RbTiOPO4 (RTP) single crystals have successfully been grown from Rb6P4O13 flux with the addition of a small amount Of MoO3 using TSSG technique. The solubility of RTP in the flux composition Rb6P4O13 has been determined. Seed crystals were obtained by spontaneous nucleation process. The seed-liquid interface was maintained by the surface tension forces, and the criteria of avoiding the solution inclusion in the initial stages of the growth are discussed. Crystals grown from Rh-incorporated platinum crucibles shift the UV cut-off towards lower wavelength. The effect of coloration and impurities on optical properties were characterized by optical absorption spectra. Single-crystal X-ray diffraction has been carried out to evaluate the lattice parameters of the grown crystals. Average dislocation density was in the range 400-5000/mm(2). Second harmonic generation (SHG) elements have been fabricated. (C) 2002 Published by Elsevier Science B.V.