Additive manufacturing is being explored as a processing technique to research and develop functionally graded ceramic composites. This report highlights the development of a direct ink writing system with multimaterial and in-line mixing capabilities for printing inks composed of high solids-loaded ceramic particulate suspensions. The custom direct ink writing system has two primary components, the print head and the feed system, and interfaces with a low-cost fused-deposition modeling 3-D printer. The feed system inputs ceramic ink to the print head at a specified composition. The print head uses an auger to mix and extrude multiple inks through a single nozzle. Precise conveyance is achieved via the auger, resulting in an improved start/stop response over syringe-based direct ink writing systems. Additionally, in-line mixing uniquely enables the formation of composition gradients. Silicon carbide and boron carbide composites were successfully printed with layered and gradient structures.