The invention describes a process for the production of EP(D)M in solution in a stirred reactor (CSTR) in which the reaction bath is kept in a boiling condition at a temperature of between 40 and 60° C. and at a pressure of between 0.6 and 1.3 MPa, and in which from 40% to 80% of the reaction heat is removed by boiling the reaction bath and the remaining reaction heat is removed by subcooling the fluids recycled to the reactor. The reactor is provided with a stirring system with three impellers, a device for distribution of the recycled fluids at the bottom of the reactor and a gamma ray level control device.