A new species of plethodontid salamander is decribed from a site along Río Quirí, a small tributary of the Río Grande de Orosí located near Tapantí, Cartago Province, Costa Rica. Bolitoglossa gracilis is a small, slender, brightly colored species that appears to be largely arboreal. The new species is a member of a species-rich salamander community. It is most similar in morphology to the smaller sympatric Bolitoglossa diminuta and the larger allopatric Bolitoglossa subpalmata. Furthermore, the allocation of the species originally described as B. diminuta is reconsidered and it is retained in this genus.