CMS results on hard diffraction

In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\tilde{\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.