The present invention provides fibronectin type III (Fn3)-based multimeric scaffolds that specifically bind to one or more specific target antigen. The invention further provides bispecific Fn3-derived binding molecules that bind to two or more target antigens simultaneously, fusions, conjugates, and methods to increase the stability of Fn3-based binding molecules. Furthermore, the present invention is related to a prophylactic, therapeutic or diagnostic agent, which contains Fn3-based multimeric scaffolds.