The effects of Krook model collisions on the electron‐electron two‐stream instability were investigated by means of a computer code. It was found that a collision frequency small in comparison with the electron plasma frequency delays the onset of saturation of the instability, decreases the total electrostatic field energy at saturation, and lowers the linear growth rates. This last effect is in very good agreement with the growth rates predicted by the linear theory of the Krook equation.