The relative stabilities and molecular structures of (Cu2S)(n) clusters were investigated at the Becke3PW91/ 6-311+G(d) level and with AIM. Three new (Cu2S)n clusters are revealed. Although all Cu-S covalent bonds are confirmed, we find that Cu-Cu covalent bonding implied/assigned in graphical geometrical structures simply on the basis of internuclear distance or overlap populations is not realized in most cases. The asymptotic behavior of stabilization energy with increasing cluster size is explained on the basis of unit coordination.