Pea, beans-phaseolus, and cowpea seeds were used in preparing protein preparations (PP, BPP, and CP, respectively). The chemical composition and functional properties (protein solubility, water/fat binding capacity, foaming ability and stability, viscosity, and emulsifying activity and stability) were examined. In comparison between the three protein preparations, PP was the highest in moisture, protein, and fat while the lowest in fiber and carbohydrates. No significant difference between the ash content of the three preparations. PP, CP, and BPP covered the needs daily recommended total indispensable amino acids for old children 3-10y and adults and can cover the total sulfur amino acids by more than 61% and the aromatic amino acids by more than 135%. PP showed higher solubility in acidic pH regions, whereas, CP showed the opposite. BPP was the highest water-binding capacity. The oil-binding capabilities of PP, BPP, and CP were similar. At pH 7.0, the foaming capacity of CP solution was double that of PP and BPP solutions. However, the foam of the BPP solution was the highest stability. The BPP was the highest in emulsifying activity and emulsion stability. From that PP, BPP and CP could be good sources of indispensable amino acids for old children 3-10 y and adults, especially aromatic amino acids. Also, they showed satisfactory functional properties as required in the manufacture of alternative food products.