This work presents the fabrication and characterization of inkjet-printed Organic Field Effect Transistors (OFETs) fabricated on flexible, plastic substrates for the detection of gaseous species. The transistors structure and fabrication process is presented, as well as their electrical characterization. Finally, the integration of biological, gas-sensitive molecules (namely, Odorant Binding Proteins) into the devices active layer is described and their response to specific Volatile Organic Compounds (VOC) is introduced and presented as results for future employment of these transistors in the field of gas sensing