A highly sensitive tyrosinase (TYR)-based amperometric biosensor is prepared using biologically designed gold nanowires (AuNWs) for pesticide detection. The AuNWs were synthesized by dodecapeptide Midas-11 and were modified with the formation of self-assembled monolayer (SAM), followed by covalent binding with TYR. The prepared TYR-AuNWs-SPCE (screen printed carbon electrode) was compared with bare, AuNWs-, modified-AuNWs-SPCE by the measurement of cyclic voltammetry. The quantitative relationship between the inhibition percentage and the pesticide concentration at the TYR-AuNWs-SPCE was obtained by measuring the current response in various concentrations of pesticides. The reasonable detection range of parathion was determined to be 0.1 ppt through 10 ppb (R2=0.990) with 0.087 ppt of detection limits. The higher sensitivity and wider detection range of the TYR-based biosensor was achieved by the use of biologically synthesized AuNWs.