Volatile organic compounds (VOCs) are a major public health concern, because of their ubiquitous nature and the possible health effects associated with exposure to them. An analytical method has been developed that enabled the determination of parts per trillion levels of 32 VOCs in 10 mL of blood. Special efforts toward reducing blank levels and improving measurement sensitivity have resulted in an analytical method that shows excellent reproducibility and recovery even at these ultratrace levels. Results on normal human blood indicate that quantifiable levels of eleven VOCs can be found in virtually all whole blood samples. In a fraction of the samples, six other VOCs can also be determined at levels above detection limits. This method shows promise as a technique for estimating the normal baseline level of VOCs in human blood and may have future applications in cases of exposure.