We study anomalous Hall conductivity of a disordered Weyl semimetal with broken time-reversal symmetry. Minimal model of such material includes two Weyl points in the first Brillouin zone. In the clean limit and at zero carrier concentration, anomalous Hall conductivity is proportional to the distance between these Weyl points and is provided solely by the Fermi arc states on the sample surface. At finite carrier concentration intrinsic part of the anomalous Hall conductivity grows as square root of the chemical potential. At the same time extrinsic contribution due to impurity scattering also appears at finite concentration of carriers. We study the model of relatively strong point-like impurities and develop a general scattering theory for this limit. As a result of this general theory we find that extrinsic part of the Hall conductivity grows as the chemical proportional to the power 3/2. Hence this type of disorder contribution quickly becomes dominant and fully determines the resulting anomalous Hall conductivity.