Coherent backscattering (CBS) of waves is an ubiquitous phenomenon showing up as soon as a wave is coherently multiply scattered in a disordered medium. It has been observed for light waves, seismic and acoustic waves but never, up to now, with matter waves. Using analytical and numerical methods, I will show that the momentum distribution of a matter wave packet launched in a random speckle potential exhibits a pronounced CBS peak. By analyzing the momentum distribution, key transport times can be directly extracted. The CBS peak can be used to prove that transport occurs in the phase-coherent regime, and measuring its time dependence permits to monitor the transition from classical diffusion to Anderson localization.