Cu-Co-Fe alloys undercooled below a certain temperature display demixing of the liquid, followed by coagulation before dendritic solidification. In this article high temperature phase equilibria in Cu-Co-Fe samples have been precisely determined by DSC. Special attention has been paid to the liquid-liquid phase separation and on its effect on the formation of microstructures. The measured transformation temperatures have also been used to update the description of the ternary phase diagram.