Abstract: Novel vectors are disclosed for expressing and secreting heterologous polypeptides from filamentous fungi. Such vectors are used in novel processes to express and secrete such heterologous polypeptides. The vectors used for transforming a filamentous fungus to express and secrete a heterologous polypeptide include a DNA sequence encoding a heterologous polypeptide and a DNA sequence encoding a signal sequence which is functional in a secretory system in a given filamentous fungus and which is operably linked to the sequence encoding the heterologous polypeptide. Such signal sequences may be the signal sequence normally associated with the heterologous polypeptides or may be derived from other sources. The vector may also contain DNA sequences encoding a promoter sequence which is functionally recognized by the filamentous fungus and which is operably linked to the DNA sequence encoding the signal sequence.