Ba(Zr(0.2)Ti(0.8))O(3)/carbon nanotube composites were prepared by spark plasma sintering and characterized by SEM and dielectric spectrometer. The composites exhibit colossal dielectric constant up to several 105 with relatively low dielectric loss over a wide temperature range from 250 to 400 K. For composite with 0.025 wt% CNTs, the dielectric constant and dielectric loss at 50 degrees C and 1 kHz were 6.1 x 105 and 0.074, respectively. The high dielectric constant can be explained by the Maxwell-Wagner polarization originating from the CNTs and Ba(Zr(0.2)Ti(0.8))O(3) interfaces and microcapacitance microstructure.