The Blagoevgradska Bistritsa (Bulgarian: Благоевградска Бистрица) is a river in south-western Bulgaria, a left tributary of the Struma. It is 41 km long and drains the southwestern parts of the Rila mountain range.^[1]

Blagoevgradska Bistritsa takes its source about 300 m southeast of the summit Golyan Mechi Vrah (2,617 m) in southwestern Rila at an altitude of 2,546 m. It initially flows a mountain stream south to Macedonia refuge, where it turns west in a deep valley covered with old-growth coniferous forests where trees reach heights of almost 60 m and protected within Parangalitsa biosphere reserve.^[1]

The river then continues to flow westwards in a deep steep valley until the village of Bistritsa, where it takes a turn to the southwest through an eroded valley. Then it forms a large alluvial cone, on which the city of Blagoevgrad is situated, and flows into the Struma at an altitude of 321 m, in Blagoevgrad's neighbourhood Strumsko.^[1]

Its catchment area covers a territory of 234 km² and represents 1.35% of Struma's total drainage basin. The largest tributary is Slavova Reka. Blagoevgradska Bistritsa has predominantly snow-rain feed with high water in late spring and early summer (May–June) and low water in winter (February). The average annual flow is 3.17 m³/s at the mouth and 2.96 m³/s at Bistritsa.^[1]

There are two settlements along the river — the city of Blagoevgrad and the village of Bistritsa, both in Blagoevgrad Province. Its waters in the lower reaches are used for irrigation.^[1] Common fish species in the river include brown trout, Struma barbel and European chub.