New recombinant binding proteins, comprising designed ankyrin repeat domain(s) with binding specificity for HER2, and comprising designed ankyrin repeat domain(s) with binding specificity for serum albumin, are disclosed, as well as nucleic acids encoding such recombinant binding proteins, pharmaceutical compositions comprising such recombinant binding proteins or nucleic acids and the use of such recombinant binding proteins, nucleic acids or pharmaceutical compositions in the treatment of diseases.