Fawn-breasted Brilliant has a large geographic range and the population trend appears to be stable. Consequently the IUCN Red List conservation status of this species is Least Concern (BirdLife International 2013). It also is not considered to the threatened under Mexican law. Fawn-breasted Brilliant is included in Appendix II of CITES, as is the case with all hummingbirds, regardless of rarity (except for Hook-billed Hermit Glaucis dohrnii, which is on Appendix I of CITES).
The relative abundance of Fawn-breasted Brilliant is assessed as uncommon and local in Colombia (Hilty and Brown 1986), as rare to uncommon and perhaps local in Ecuador (Ridgely and Greenfield 2001a), and as uncommon in Peru (Schulenberg et al. 2010).