Nb2O5 in the high niobia structure type can accommodate approximately 25% partial substitution of Ta for Nb in a solid solution. Here we report the dielectric properties of polycrystalline ceramics of (Nb1-xTax)(2)O-5, 0.0 less than or equal to x less than or equal to 0.25, in the frequency range 1kHz-3MHz, in the vicinity of ambient temperature. The substitution of even small quantities of Ta for Nb greatly enhances the dielectric constants, reaching a maximum of approximately 180 at ambient temperature for x = 0.15.