The welding of Cu55Ni45 alloy to titanium and stainless steel has not been reported in the scientific literature, which motivated us to perform the present weldability study of Cu55Ni45/Ti-6Al-4V and Cu55Ni45/316L combinations using a continuous Yb:YAG laser with 1030 nm wavelength. Different laser spot offsets from the joint line were tested in search of optimal dilutions. Microstructure and mechanical properties of the joints were investigated.The Cu55Ni45/Ti-6Al-4V melted zones exhibited elevated hardness due to the formation of intermetallic phases, but contained no microcracks. The highest UTS of 250 MPa was reached for the lowest titanium dilution that resulted in average melted zone hardness of ~400 HV. On the other hand, Cu55Ni45/316L melted zones exhibited a hardness similar to those of base materials for all dilutions. All Cu55Ni45/316L joints demonstrated a ductile behavior during the tensile test, with average UTS values of 446 MPa, and fractured in solid Cu55Ni45 insert.