The Sandanska Bistritsa (Bulgarian: Санданска Бистрица) is a river in south-western Bulgaria, a left tributary of the Struma.

[1][2] The river is 33 km long and drains the south-western sections of the Pirin mountain range.

After the confluence with the first significant right tributary, the Bashliytsa, the turns to the south-west and flows in a deep sparsely forested valley.

[3] Near the town of Sandanski the river enters the Sandanski–Petrich Valley forming a large mucous cone.

The river's waters are utilised for electrical power generation with three hydropower plants at Popina Luka, Lilyanovo and Sandanski I with a total installed capacity of 56 MW, as well as for irrigation.