The gastric pathogen <i>Helicobacter pylori</i> activates the NF-κB pathway in human epithelial cells <i>via</i> the recently discovered α-kinase 1 TRAF-interacting protein with forkhead-associated domain (TIFA) axis. We and others showed that this pathway can be triggered by heptose 1,7-bisphosphate (HBP), an LPS intermediate produced in gram-negative bacteria that represents a new pathogen-associated molecular pattern (PAMP). Here, we report that our attempts to identify HBP in lysates of <i>H. pylori</i> revealed surprisingly low amounts, failing to explain NF-κB activation. Instead, we identified ADP-<i>glycero</i>-β-D-<i>manno</i>-heptose (ADP heptose), a derivative of HBP, as the predominant PAMP in lysates of <i>H. pylori</i> and other gram-negative bacteria. ADP heptose exhibits significantly higher activity than HBP, and cells specifically sensed the presence of the β-form, even when the compound was added extracellularly. The data lead us to conclude that ADP heptose not only constitutes the key PAMP responsible for <i>H. pylori</i>-induced NF-κB activation in epithelial cells, but it acts as a general gram-negative bacterial PAMP.-Pfannkuch, L., Hurwitz, R., Traulsen, J., Sigulla, J., Poeschke, M., Matzner, L., Kosma, P., Schmid, M., Meyer, T. F. ADP heptose, a novel pathogen-associated molecular pattern identified in <i>Helicobacter pylori</i>.