The present invention relates to a rappel line clamp and harness with which the descent down a rope may be readily controlled. The rappel line clamp and harness of the present invention includes a first and a second elongated juxtaposed plate. The pair of plates includes opposing and remote sides. The plates define corresponding first and second longitudinal marginal portions and a corresponding first and second transverse end marginal portions. The first pair of corresponding longitudinal marginal portions include a means for pivotally interconnecting the plates for limited swinging apart of a second pair of corresponding longitudinal edge portions. The opposing sides of the plates include full length opposing and registered longitudinal open ended grooves formed therein approximately intermediate between the plate longitudinal marginal portions. The second pair of corresponding longitudinal marginal portions of the plates include coacting adjustable clamp means so that said second pair of corresponding longitudinal marginal portions may be adjustably clamped together to thereby clamp a flexible member between the portions of the opposing sides of the plates defining the grooves.