TRANSLOCATED heat injury is common in burns of human beings1 but is apparently not recorded in plants. When one of the two primary leaves of pinto bean (Phaseolus vulgaris L.) or cowpea (Vigna sinensis ((Torner) Savi) or the cotyledons of National Pickling cucumber (Cucumis sativus L.) was heated in water (5 sec. at 70° C. was suitable) and the opposite leaf abraded as in mechanical inoculation with viruses, the heated leaf was killed and the unheated leaf was severely injured. There was no apparent injury to the petioles and stem through which the injury stimulus passed. When the heated leaf was removed from the plant within 4 hr. after heating, the translocated injury to the opposite leaf was prevented, or recovery was favoured. Translocated injury still occurred if heating followed abrasion by as much as 12 hr., or if abrasion followed heating by as much as 16 hr., but comparable injury never occurred from abrasion or heat only. As the ratio of the area of the heated leaf to that of the unheated leaf was increased by removal of part of the leaf area, translocated injury was increased. The time of day to produce maximum translocated injury quickly was in the morning, but translocated injury could be produced at any time of day. Translocated injury was favoured by light and high temperatures in the environment. As the age of plants was increased from 12 to 23 days the degree of translocated injury was increased. The temperature coefficient for translocated heat injury was about 10. This translocated heat injury had various effects on infections which will be reported elsewhere. While no chemical responsible for translocated heat injury has been demonstrated, these results suggest a similarity between translocated heat injury in plants and animals.