The title compound, C(15)H(19)NO(4), contains one crystallographically independent mol-ecule in the asymmetric unit. The N-O-C-O torsion angle is 1.97 (9)°. The two pairs of vicinal H atoms that lie above or below the plane defined by the five-membered pyrrolidine-2,5-dione ring are an average of 6.57 (5)° from being eclipsed. The average absolute C-C-C-C torsion angle in the adamantane skeleton, in which each fused cyclo-hexane ring is in a chair configuration, is 59.99 (5)°. The crystal packing is unremarkable.