Leptobrachium kanowitense was formerly known as L. nigrops. The latter has been split up into L. ingeri and L. kanowitense. L. kanowitense is a species of lowland rainforests in inland areas of Sarawak. Leptobrachium kanowitense is differentiated from L. ingeri by less developed toe webs and by having less pointed finger tips. L. kanowitense has dark blotches only at the groin and posterior thigh; the thigh is whitish ventrally with some dots.The tympanum is uniformly colored. The dorsum lacks the markings seen in L. ingeri. 

Females reach a snout-vent length of up to 39–45 mm, males are around 33 mm. The call is a series of 5–10 notes.