The cerebral metabolic rate of oxygen of small animals can be reliably imaged using the in vivo 17O magnetic resonance approach at high field. However, a separate measurement is required for imaging the cerebral blood flow in the same animal. In this study, we demonstrate that the 17O NMR signal of metabolically produced H217O in the rat brain following an 17O2 inhalation can serve as a perfusion tracer and its decay rate can be used to determine the absolute values of cerebral blood flow across a wide range of animal conditions. This finding suggests that the in vivo 17O magnetic resonance approach is capable of imaging both cerebral metabolic rate of oxygen and cerebral blood flow simultaneously and noninvasively; and it provides new utilities for studying the cerebral oxygen metabolism and perfusion commonly associated with brain function and diseases. Magn Reson Med 70:309–314, 2013. © 2012 Wiley Periodicals, Inc.