Composite films of polyacrylonitrile (PAN) and multiwalled carbon nanotubes (MWNTs) have been prepared by gelation/crystallization from solution. The contents of MWNTs were 5-10 wt.-%, measured against PAN. The electrical and mechanical properties have been studied in comparison with those of the homopolymer PAN films prepared from the same method. Furthermore, stabilization and the carbonization have been carried out by using the drawn PAN-MWNTs as a new precursor to prepare carbon films with a cross-sectional area much larger than that of a commercial carbon fiber (>3000 times). The MWNTs within the PAN matrix promote the formation of a condensed aromatic ladder structure during the stabilization process and play an important role in preparing PAN-based carbon material with high carbon quality and high mechanical properties. When the stabilized composites with 10 wt.-% MWNTs are carbonized at 1000degreesC, the Young's modulus reaches 37.5 GPa, and the electrical conductivity reaches 10(2) S cm(-1). The carbonized PAN homopolymer does not form an adequately robust bulk film for the mechanical properties to be measured.