Telmatobius macrostomus, also known as the Lake Junin (giant) frog or Andes smooth frog, is a very large and endangered species of frog in the family Telmatobiidae, endemic to altitudes of 3,200–4,300 m (10,500–14,100 ft) in the Andes of Junín in central Peru. It is completely aquatic and almost entirely restricted to lakes (such as Lake Junín), but it has also been introduced to the upper part of the Mantaro River. It is among the largest frogs in the world, measuring up to 70 cm (28 in) in full length. It is mainly threatened by capture for human consumption and predation by introduced species (trout), but potentially also by pollution.