Using the impedance analysis, we obtain the dielectric constants of RbTiOAsO4 (RTA) single crystals for the three principle crystallographic axes in the frequency range of 1 kHz-6 MHz and in the temperature range of 303-1123 K. The conductivity of RTA along the polar c axis is five orders-of-magnitude smaller than that of KTiOPO4 (KTP) in the temperature range of 500-970 K. The conductivities of RTA along the three principle axes have the same order of magnitude, 10(-5) Omega(-1) m(-1) at 720 K, which is contrasted with the high anisotropy shown in KTP. (C) 1999 American Institute of Physics. [S0003-6951(99)01334-0].