We provide an overview of the taxonomy, ecology, and biogeography of the epiphytic cacti of Bolivia, which is second only to southeastern Brazil as a centre of epiphytic cactus diversity in South America. Twenty-one obligatory or facultative epiphytic species with 2 varieties in 7 genera occur in Bolivia. A further 14 species in 6 normally terrestrial genera are recorded as accidental epiphytes. Two taxa are described as new: Lepismium asuntapatense sp. nov. M. Kessler, P.L. Ibisch & Barthlott and Rhipsalis baccifera ssp. nov. cleistogama M. Kessler, P.L. Ibisch & Barthlott. Eight species are endemic to Bolivia, mostly in humid montane forests. Preliminary ecograms and extrapolated range maps for all obligatory epiphytes are provided. GIS-overlay of the range maps is used to predict the species diversity patterns for all obligatory epiphytes and for the genera of Rhipsalideae. Species-richness is highest in humid montane forests, but physiognomically and in relation to overall species-richness of vascular epiphytes, epiphytic cacti are most important in semi-humid montane forests of inter-Andean valleys and the Chaco zone. Three species are classified as vulnerable and all others as not endangered.