Cryonics (from Greek: κρύος kryos meaning 'cold') is the low-temperature freezing (usually at −196 °C or −320.8 °F or 77.1 K) and storage of human remains, with the speculative hope that resurrection may be possible in the future. Cryonics is regarded with skepticism within the mainstream scientific community. It is generally viewed as a pseudoscience, and its practice has been characterized as quackery.

Cryonics procedures can begin only after the "patients" are clinically and legally dead. Cryonics procedures may begin within minutes of death, and use cryoprotectants to try to prevent ice formation during cryopreservation. It is, however, not possible for a corpse to be reanimated after undergoing vitrification, as this causes damage to the brain including its neural circuits. The first corpse to be frozen was that of James Bedford in 1967. As of 2014, about 250 bodies had been cryopreserved in the United States, and 1,500 people had made arrangements for cryopreservation of their corpses.

Critics argue that economic reality means it is highly improbable that any cryonics corporation could continue in business long enough to take advantage of the claimed long-term benefits offered. Early attempts of cryonic preservations were performed in the 1960s and early 1970s which ended in failure with all but one of the companies going out of business, and their stored corpses thawed and disposed of.