Pulsating heat pipes provide an extremely effective method for transferring heat. Several unique features of the cryogenic version of the PHP that have appeared in the recent literature are discussed. These include stable operation with the evaporator in the supercritical region, a temperature dependent fill ratio, and a length invariant conductance for the helium PHP. Results for helium, neon, hydrogen, and nitrogen PHPs are included along with performance dependence on orientation, fill level, and number of parallel tubes.