By visualizing DNA with diamidino phenylindole (DAPI), we found that hypothermal incubation followed by rewarming of human neutrophils resulted in an increased number of DAPI-positive objects representative of extensive DNA unfolding seemingly similar to neutrophil extracellular traps (NETs). In contrast to canonical NET formation, diphenylene iodonium (DPI), an NADPH oxidase inhibitor, exhibited negligible effects on formation of the DAPI-positive objects. Moreover, multiple instances of DNA damage were detected in the objects, but not in canonical NETs. Our results thus suggest the potential of hypothermia for triggering DNA structural alteration in neutrophils, which is similar to but distinct from NET formation.