The equiatomic CoCrCuFeNi alloy is composed by two phases of distinct melting points, opening the possibility of employing the semisolid technology, which offers advantages over conventional casting and forging. It is believed that the increase of Cu in the CoCrCuFeNi alloy leads to a higher volume fraction of the Cu-rich phase with lower melting point. Therefore, the present work aimed to study the influence of Cu on the microstructure of CoCrCuFeNi alloys in the semisolid state. For this purpose, samples with different Cu contents were submitted to isothermal heat treatments between the solidus and liquidus. The results showed that it is possible to effectively control the volume fraction of the existing phases by modifying the alloy composition. Accordingly, higher liquid fractions at a same temperature can be obtained with increased Cu content. Furthermore, all samples presented fine and globular primary particles, demonstrating their favorable characteristics for semisolid processing.