A pulse sequence for a two-dimensional inverse Laplace transform NMR experiment is proposed and demonstrated. The experiment is analogous to the two-dimensional Fourier transform protocol called EXSY, but detects exchange by monitoring alterations in the transverse relaxation time rather than the NMR frequency. The sequence may be useful for measurement of exchange and diffusion of water in vivo and for detecting slow exchange phenomena in glassy polymers. The application of the Fourier transform (FT) to nuclear magnetic resonance spectroscopy' and its extension to multiple dimensions2 has radically altered modern chemistry and medical science; NMR imaging3 and the determination of the structure of proteins in solution4 are two important advances that would be either impossible or orders-of-magnitude more difficult without the FT. The crucial feature of the transformation is the increase in availablespectroscopic resolution. If two signals havedifferent precession frequencies VI and vs as a result of some coherent interaction, the time evolution of the total transverse nuclear magnetization M(r) will be the sum of the time evolution of these two species (M1(t) + Ms(t)), and at every point in time it will be dependent on VI and us. However, the FT will still show resolved signals in frequency space, thus discriminating the contributions of the two species.