The main objective of this work is to determine the wetting behaviour of lead-free solders on copper substrates in view of their applications in electronic industry. The wetting behaviour of X–In–Sn (X=Au, Bi) ternary molten alloys in contact with copper has been studied and compared with the corresponding behaviour of their binary subsystems with a particular attention to the In–Sn/Cu system. The contact angle measurements on Cu-plates were performed by using a sessile drop apparatus. The solder/copper interface was characterised by the SEM-EDS analysis.