Routine low-blank chemistry and 0.01--0.04% precision on the ratio 176Hf/177Hf allows study of Hf isotopic variations, generated by &bgr;--decay of 176Lu, in volcanic rocks derived from the suboceanic mantle. Normalized to 176Hf/177Hf=0.7325, 176Hf/177Hf ranges from 0.2828 to 0.2835, based on 24 basalt samples. 176Hf/177 Hf is positively correlated with 143Nd/144Nd, and negatively correlated with 87Sr/86Sr and 206Pb/204Pb. Along the Iceland-Reykjanes ridge tranverse, 176Hf/177Hf increases southwards. The coherence of Hf, Nd and Sr isotopes in the oceanic mantle allows an approximate bulk Earth 176Hf/177Hf of 0.28295 to be inferred from the bulk Earth 143Nd/144Nd. This requires the bulk Earth Lu/Hf to be 0.25, similar to that of the Juvinas eucrite. 60% of the Hf isotopic variation in oceanic basalts occurs among mid-ocean ridge samples. Lu-Hf fractionation probably decouples from Sm-Nd and Rb-Sr fractionation in very depleted source regions, with high Lu.Hf, and consequent high 176Nf/177Hf ratios developing in mantle residual from partial melting.