The size-effect of Kondo-scattering in nanometer-sized metallic point contacts is measured with the simplified, mechanically-controlled break–junction technique for CuMn alloy of different Mn concentrations: 0.017; 0.035; and 0.18 (±0.017) at.&percent;. The results are compared with our previous publication on nominally 0.1 at. &percent; CuMn alloy.12The increase of width of the Kondo resonance and enhanced ratio of Kondo-peak intensity to electron–phonon scattering intensity is observed for contacts with sizes smaller than 10 nm. From the comparison of electron–phonon scattering intensity for the pressure-type contacts, which correspond to the clean orifice model, we conclude that the size effect is observed incleancontacts with the shape of achannel(nanowire). ©1998 American Institute of Physics.