Abstract: Methods for the recombinant production of saporin-containing proteins, including cell surface binding protein-saporin fusion proteins, are provided. The resulting fusion proteins are cytotoxic to targeted cells. In preferred embodiments, methods are provided for the production of basic fibroblast factor (bFGF)-saporin fusion proteins by culturing Escherichia coli that has been transformed with a vector containing DNA encoding bFGF linked via a spacer peptide to the amino terminus of a cytotoxic portion of a saporin polypeptide to obtain expression of the DNA, and isolating the resulting FGF-saporin fusion protein. FGF-saporin fusion proteins and saporin proteins containing from about 5 to 12 amino acid N-terminal extensions are also provided.