A soy protein-based water-soluble binder composition for natural fiber nonwoven fabric is discussed in this paper. Before applying to viscose fibers, foam decay studies of soy protein and acrylic binders are carried out and results are compared. The bio-binder (soy protein and sodium dodecyl sulphate modified soy protein) composition effectively binds natural fibers in a nonwoven fabric by foam application method. Such fabrics are widely used for industrial wipes and non-reusable products such as diapers, sanitary napkins, bandages, etc. The mechanical and thermal properties of viscose fabric bonded with soy protein bio-binder are compared with the same fabric produced with commercially applied acrylic binder. Scanning electron microscope was used to confirm the bonding of the viscose fiber with the bio-binders.