The 1H NMR spectra of the arylcopper(I) compounds o-, m-, p-tolyl, o-anisyl-, (2,4-dimethylphenyl)copper are described. The resonance peaks of the aromatic protons and the protons of methyl groups ortho to the metal atom are shifted downfield with respect to those of the free arenes, while those from meta and para positions are slightly shifted upfield. The spectrum of o-anisyl copper, shows anomalous and much larger effects, and possible explanations of this are advanced. Magnetic anisotropy centered between carbon and copper is suggested to be the main factor influencing the proton shielding constants. The temperature dependence of some spectra, indicates that there is hindrance to rotation for methyls ortho to copper.