Placobdella ali, n.sp., a sanguivorous glossiphoniid leech, is described from material collected in Harriman State Park, approximately 50 km north of the island of Manhattan, New York City. The new species resembles Placobdella ornata and could be easily confused with Placobdella papillifera. Dorsal papillation and internal reproductive anatomy distinguish P. ali from existing descriptions of the latter. Ventral pigmentation and salivary anatomy distinguish it from the former.