Pogonotriccus bristle tyrants are a small group of flycatchers for which few data on nest architecture are available. I describe the nest of Marble-faced Bristle Tyrant (P. ophthalmicus) from eastern Ecuador. The nest was an oven-shaped, mossy ball with a hooded side entrance attached by the back to the trunk of a large tree. I discuss aspects of nest architecture, composition, and placement which may prove useful for resolving phylogenetic hypotheses within the Leptopogon-Pogonotriccus-Psetidotriccus clade of pipromorphine flycatchers. These characters, in particular nest attachment and construction, support a close relationship between Pogonotriccus, Pseudotriccus, and Corythopis. The switch from draping material to stuffing material during construction may be a key innovation uniting these genera.