["Psychophysiology, Volume 63, Issue 5, May 2026. ", "\nABSTRACT\nInteroceptive attention refers to selectively attending to internal bodily signals to guide perception and behavior. Cardiac interoception, in particular, has been proposed to play a key role in self‐regulation and emotional awareness, yet the neural dynamics underlying attention to cardiac signals remain incompletely understood. Here, we investigated whether heartbeat‐locked beta‐band (16–28 Hz) activity serves as an oscillatory marker of interoceptive attention. Using magnetoencephalography (MEG), we recorded neural activity from 51 healthy participants during heartbeat and auditory discrimination tasks. Time–frequency analyses revealed significant suppression of beta‐band power 310–530 ms after the R‐peak, localized to somatosensory cortex, premotor cortex, dorsolateral prefrontal cortex, and midline cingulate regions. This heartbeat‐locked beta suppression was observed not only during task conditions but also at rest, suggesting an ongoing cortical response to cardiac signals. Critically, the magnitude of suppression was significantly enhanced during interoceptive attention. Moreover, greater beta suppression in somatosensory and anterior cingulate cortices was associated with higher interoceptive accuracy across individuals. Control analyses indicated that the effect was time‐locked to cardiac events and was not observed in surrogate epochs, making it unlikely to reflect nonspecific timing effects or heart rate variability. Heartbeat‐locked beta suppression was enhanced during interoceptive attention and was larger in participants with higher interoceptive accuracy. The results identify beta‐band suppression as a candidate oscillatory marker of interoceptive attention and provide a foundation for future studies of interoceptive processing in healthy and clinical populations.\n"]