Erpobdella mestrovi is a species of troglobitic leech found only in deep caves in Northern Velebit, part of the Dinaric Alps of Croatia. The leech was first found in Lukina jama in 1994, which at 1431 meters deep is the deepest cave in Croatia. The leech has been found in several other caves systems in Velebit such as Slovacka jama (-1320 m), Olimp (-531 m) and Velebita (-1026 m), and is currently considered endemic to Croatia.