A series of the twinned 8H hexagonal perovskites in the Ba4LiNb3-xTaxO12 (x=0-3) system were synthesized by the conventional solid-state reaction method. Ba4LiNb3-xTaxO12 solid solutions were single phase in the whole range of x values. The ceramics exhibit perfect microwave dielectric properties with relative permittivity, epsilon(r)similar to 28-37, high quality factor, Q x f similar to 37 000-104 000 GHz, and temperature coefficient of resonant frequency, tau(f)similar to+25-+65 ppm/degrees C.