The Smradlivo Lake (Bulgarian: Смрадливото езеро [smrɐdˈlivoto ˈɛzɛro]) is a glacial lake located in the central section of the Rila mountain range, south-western Bulgaria.

It is the second of the five Smradlivi Lakes and is situated at an altitude of 2,298 m in a hanging valley facing the valley of the Rilska River to the north between the summits of Rilets (2,713 m) to the south-west and Kyoravitsa (2,612 m) to the south.

[2] The Smradlivoto Lake is oval shaped with a maximum length of 900 m the width of 260 m. With a surface area of 212,000 m2 (21.2 ha) it is the largest glacial lake in Bulgaria and the Balkan Peninsula.

[1] Its outflow is at the northern end, forming a stream that flows into the Rilska River, a left tributary of the Struma, after 1.2 km.

Many legends about the lake are linked with the 10th-century medieval Bulgarian hermit and saint John of Rila who found refuge in the nearby valleys and established the Rila Monastery.