The lattice dynamics of 12 chalcopyrite type compounds CuAlS2, CuGaS2, CuInS2, AgGaS2, AgGaSe2, AgInSe2, ZnSiP2, ZnGeP2, CdSiP2, CdGeP2, CdSnP2, and CdGeAs2 have been investigated based on a rigid ion model. As the anisotropy of the dynamic charges is not very pronounced the calculations were done assuming isotropic charges. The calculated force constants, normal co-ordinates and potential energy distributions are compiled and discussed.