We have investigated the evolution of the magnetic properties on the Ce(In 1−x Cu x) 2 (0 < x ≤ 0.3) series of alloys. The orthorhombic structure of the CeIn 2 alloy (Imma) changes into the hexagonal AlB 2 -type (P6/mmm) for x = 0.05 and, then, into the hexagonal CaIn 2 -type (P6 3 /mmm) for higher Cu concentrations, up to x = 0.3. The dc (ac) magnetic susceptibility shows an abrupt decrease of the magnetic transition temperature from 22 K to 5.4 K (x = 0.05). The results indicate the influence of the crystallographic type of structure and disorder effects on the magnetic behavior along the series.