The species Bathysa gymnocarpa K.Schum is a tree belonging to the Rubiaceae family, endemic in Brazil. So far, there are reports neither of phytochemical work nor of biological evaluation of it. The analysis by High Performance Liquid Chromatography coupled to a Diode Array Detector and a tandem Mass Spectrometer with an Electrospray Ionization source (HPLC-DAD-ESI-MS/MS) of its crude extract allowed to characterize in a complex mixture, without isolation, fourteen compounds, being two as cinnamic acid derivatives, and the others as mono-, di-and triglycosilated derivatives of the flavonols quercetin and kaempferol. These compounds are reported for the first time in Bathysa spp.