Tubular polypyrrole (PPy) could be synthesized by in situ doping polymerization in the presence of p-naphthalene sulfonic acid (NSA) as dopant. The resultant tubular PPy-NSA not only exhibits high room temperature conductivity (sigma(RT) = 10 S/cm) but is also soluble in m-cresol. The molecular structure of PPy-NSA is identical to the characteristic structure of PPy synthesized by a conventional method. It has been demonstrated that NSA dopant with large molecular size and plate-lebe structure is a key factor to control formation of tubular PPy-NSA.