The present invention provides recombinant filamentous fungal host cells producing one or more secreted polypeptide of interest, said cells comprising in their genome at least one nucleic acid construct comprising a first polynucleotide encoding a signal peptide operably linked in translational fusion to a second polynucleotide encoding the polypeptide of interest, wherein the first polynucleotide is heterologous to the second polynucleotide, wherein the first polynucleotide is a polynucleotide having at least 70% sequence identity with SEQ ID NO:1 or a polynucleotide encoding a signal peptide having at least 70% sequence identity with SEQ ID NO:2, as well as methods of producing one or more secreted polypeptide of interest.