The acid-catalysed methanolysis of D(+)-(1,2-epoxyethyl)benzene has been studied polarimetrically. A corrected value of the optical purity of a sample of this epoxide has been determined by g.l.c. The major product of the reaction, L(+)-1-methoxy-2-phenylethanol, has been synthesised. Analysis of the product of acid-catalysed methanolysis indicates that 89% inversion of configuration occurs. This is interpreted in terms of a borderline A2 mechanism. A kinetic study of the reaction spectrophotometrically and polarimetrically supports this interpretation.