Abstract: The present invention provides a powerful new method for producing, uniform sized and uniformly aligned nanotubes through catalytic pyrolysis of a hydrocarbon within the dense, uniform and parallel pores of alumina nano-templates. The catalyst, Co, Fe, Ni or another suitable substance is deposited electrochemically into the bottom of the channel of the alumina template. The nanotubes with any desired diameter in the range 5-500 nm and lengths up to .about.100 .mu.m, are generated by the pyrolysis of a suitable hydrocarbon inside the pores of the alumina template with at least one end open at the alumina/air interface. The nanotubes may be filled by metals using for example electroless deposition.