We present a series of organic thin film transistor (OTFT) devices realized by vacuum evaporation, spin-coating, drop casting and inkjet printing and a comparative analysis of their electrical response/behavior obtained under identical measurement conditions. A small molecule, alpha,omega-hexyl-distyryl-bithiophene DH-DS2T, was used as a hole transporting active layer. Structure and morphology of thin films have been studied by atomic force microscopy, X-ray diffraction and optical microscopy. Different parameters linked directly to the processes (solvent, concentration, deposition method, surface, post-treatment...) are identified as key factors controlling film quality/crystallinity and device performances. This systematic study reveals the factors that limit efficient charge transport at the macroscopic scale of the channel length in OTFT devices. (C) 2010 Elsevier B.V. All rights reserved.