Studies of a synthesis of KTaO3 displayed a two-step reaction path with the intermediate formation of K2Ta4O11. Thermal and X-ray diffraction analysis showed that the synthesis is completed at 900 degrees C. Sintering studies showed that KTaO3 powder can produce single phase ceramics with 85% of relative density with the addition of 5% of potassium excess when sintered at 1330 degrees C for 1 h. Longer sintering times or higher temperatures result in enhanced potassium loss and consequent formation of K6Ta10.8O30 secondary phase with tetragonal tungsten bronze structure. Room- and low-temperature microwave dielectric properties of KTaO3 ceramics compare well with measurements performed on single crystals. We evaluated the influence of microstructural features (porosity, structural defects, secondary phases) on the dielectric properties of the ceramic samples.