Cooperative growth of pearlite is simulated for eutectoid steel using the multi-phase field method. This allows to take into account diffusion of carbon not only in γ phase, but also in α phase. The lamellar spacing and growth velocity are estimated for different undercoolings and compared with experimental results from literature and theoretical results from analytical models. It is predicted, that diffusion in ferrite and growth of cementite from the ferrite increase the kinetics of pearlitic transformation by a factor of four as compared to growth from austenite only, which is assumed by the classical Zener-Hillert model. Further on the effect of stress due to inhomogeneous carbon distribution in austenite and due to transformation strain is discussed shortly.