We examined the seif-organized properties of regioregular poly(3-alklylthiophene)s(HT-PATs) in Langmuir-Blodgett(LB) films by X-ray diffraction and FT-IR measurements. The HT-PATs showed self-organized properties due to their stereoregularity. The pendent decyl groups of HT-PDT formed more planar conformation and interdigitated structure. Electrical conductivities of doped HT-PATs/SA LB films were dramatically improved compared with random PATs, and HT-PDT films showed the highest in-plane conductivities among HT-PATs LB films.