Polyaniline doped with dodecylbenzene sulfonic acid and conductive carbon black (PAn.DBSA/CB) hybrid materials have been prepared by hi situ polymerization. The electrical resistivity of the PAn/CB was measured as a function of CB. The minimum resistivity was noticed for the composites with 25 wt % of CB as compared to other systems. Small angle x-ray diffraction data was used to characterize the molecular arrangements of these composites. The refinement parameters such as periodicity (L), phase lengths (< Y > and < Z >), phase ratio (< Y >/< Z >), and probability distribution of phases [gamma z (crystalline), gamma(Y) (amorphous)] for PAn, CB, and PAn/CB composites have been measured by SAXS data. It was observed that there is decrease in the crystallinity with increase in CB content in the composites. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 673-679, 2010