Amaranth-oat composites were developed using gluten free amaranth flour containing essential amino acids and minerals with oat products containing β-glucan, known for lowering blood cholesterol. Amaranth flour and oat bran concentrate (OBC) composites (1:4) were processed using different technologies, including dry mixing, baking, steaming, cold wet blending, and high speed homogenizing (Polytron PT6000) with cold water or hot water. The results showed that water holding capacities, pasting, and rheological properties were dramatically increased by wet blending, Polytron with cold water, and Polytron with hot water followed by drum drying. The processing procedures created dissimilar physical properties that will enhance the application of ancient grains and oat for functional foods that are suitable for people who are gluten-intolerant. In addition, the dietary fiber contents of composites were increased by the incorporation of OBC. The composites can be inexpensively prepared and processed. The new healthful products will be affordable for people who suffer from celiac disease or gluten-intolerant. These innovative gluten-free functional food products will help millions of gluten sensitive consumers enjoy heart-healthy functional foods.