Nuclear magnetic resonance imaging of deuterium is demonstrated in cat brain in vivo and in situ at 4.7 T magnetic field strength. Images were acquired at 4–5% deuterium enrichment, using D2O as a nuclear spin label, with as little as 10‐s time resolution. This suggests the potential application of D2O as an exogenous MRI label for quantitative flow imaging or contrast enhancement. The efficient quadrupolar relaxation mechanism of the deuterium nuclide results in a short ca. 250 ms spin–lattice relaxation time (T1). This allows for rapid signal averaging, thus increasing signal‐to‐noise in the deuterium image. Additionally, three widely dispersed deuterium spin–spin relaxation times (T2) are observed of ca. 10, 40, and 400 ms which provide high compartmental image contrast, thus yielding information of physiological as well as anatomical interest. T2‐weighted deuterium cerebral images are presented showing marked tissue relaxation discrimination. © 1988 Academic Press, Inc.