Stenoma pertinax is a moth of the Depressariidae family. It is found in Peru. The wingspan is about 17 mm. The forewings are light ochreous with a dark purple-fuscous irregular blotch on the base of the costa, reaching nearly half across the wing. There is a dark purple-fuscous spot on the costa before the middle. The plical stigma is very small and dark fuscous, the second discal is rather large and quadrate and there is a broad rather dark purple-fuscous terminal fascia, anterior edge running from five-sixths of the costa to two-thirds of the dorsum, with a projection above the middle where a train of several indistinct dots of dark fuscous irroration runs to the costal spot, and a convex-prominent on the lower third so as to touch the second discal stigma beneath, including a suffused p