We demonstrate the first guiding of cold atoms through a 88mm long piece of photonic band gap fiber. The guiding potential is created by a far-off resonance dipole trap propagating inside the fiber with a hollow core of 12 mu m. We load the fiber from a dark spot Rb-85 magneto-optical trap and observe a peak flux of more than 105 atoms s(-1) at a velocity of 1.5 ms(-1). With an additional reservoir optical dipole trap, a constant atomic flux of 1.5x10(4) atoms s(-1) is sustained for more than 150 ms. These results open up interesting possibilities to study nonlinear light-matter interaction in a nearly one-dimensional geometry and pave the way for guided matter wave interferometry.