Approaching objects pose potential threats to an organism, making it advantageous for sensory systems to detect such events rapidly and efficiently. Evidence from nonhuman primates would further suggest that multisensory integration of looming auditory-visual stimuli is enhanced relative to those that recede (Maier et al., 2004). Whether such extends to humans and what brain mechanisms contribute to such effects remain largely unknown. We therefore studied the influence of looming, receding, and stationary sounds on visual cortex excitability; the latter of which was indexed by phosphene detection following single-pulse TMS over the occipital pole (Romei et al., 2007). The pulse was applied at auditory stimulus offset (the duration of which varied) and was fixed at a sub-phosphene threshold intensity (85%). Linear sound intensity changes led to the perception of looming or receding sounds (rising and falling changes, respectively), and control sounds were presented at constant intensity. Visual cortex excitability was dramatically increased by looming relative to either receding or stationary sounds (on average by about 80%), irrespective of the sound duration. This provides novel insight into modulatory, multisensory mechanisms within low-level visual cortex as a basis for efficient visual processing in the presence of auditory looming sounds.