A purified insulin-like growth factor binding protein (IGFBP) selected from the group consisting of insulin-like growth factor binding protein having an amino acid sequence that, preferably, is at least 70% homologous to the amino acid sequence of FIG. 1 and fragments thereof that are capable of binding to an antibody specific for the protein or to an insulin-like growth factor is described. This new IGFBP is designated herein as IGFBP-5. Recombinant DNA molecules encoding the binding proteins and subsequences thereof are also described along, with recombinant microorganisms and cell lines containing the DNA molecules and methods for producing the binding proteins using recombinant hosts containing the relevant DNA molecules. Antibodies to the protein, useful in various diagnostic applications, are also described.