Abstract Inflammatory responses that are generated during viral infections are critical for protective anti-viral immune responses. The exact viral-derived structures (also known as pathogen-associated molecular patterns, PAMPs) that activate uninfected cells to induce pro-inflammatory signals are not completely characterized. To date, the viral PAMPs that are identified include dsRNA and 5' triphosphate ssRNA, which are recognized by several cellular pathways such as SR-A, PKR, RIG-I, TLR-3 and MAVS. During viral infections, the cellular enzyme ADAR-1 (adenosine deaminase acting on RNA-1) catalyzes conversion of adenines to inosines, which is a pathway for blocking viral replication. ADAR-1 activation in the infected cells leads to the presence of inosine-containing viral and cellular RNA (Ino-RNA). Here, we provide in vitro and in vivo data to affirm our hypothesis that the release of Ino-RNA from infected cells and its interaction with surrounding uninfected cells is a potent stimulus for inflammatory innate immune responses. Treatment of primary human bronchial epithelial (PHBE) cells or C57BL/J6 with in vitro synthesized Ino-RNA rapidly and potently induced several markers of innate immune response such as IFN-β, TNF-a, IL-6 and RANTES. Our data uncovers a novel strategy for uninfected host cells to detect viral infections in the surrounding tissue.