RbTiOPO4 crystals have been grown by the top-seeded solution method from self-fluxes containing [Rb]/[P] molar ratios as high as 2.3 and initial solute concentrations of 1.2g-RTP/g-flux, corresponding to the previously unexplored part of the RTP crystallization field in the Rb2O-P2O5-TiO2 ternary system. The Curie temperatures of as-grown crystals corresponding to the high-temperature ferroelectric phase transitions have been determined using the standard dielectric (capacitance) technique and found to exceed 790 degrees C. The results indicate that the Curie points shift to higher values as compared with crystals grown from fluxes with lower [Rb]/[P] molar ratios, as expected, still maintaining the usual linear dependence between the Curie point magnitude and flux chemical composition. However, the room temperature dc resistivity is distributed uniformly within a large single crystal, both radially and axially, reaching high values between 10(11) and 10(12)Omega cm. The temperature dependence of the ac conductivity has been studied as well and discussed in terms of the site-occupancy of Rb+-ions and ionic migration paths in nearly stoichiometric RTP crystals. (C) 2007 Elsevier B.V. All rights reserved.