The leaves of Passiflora alata Curtis (an official species in the Brazilian Pharmacopoeia) are used to treat anxiety, as antispasmodics and sedatives. The development of new analytical methods for analysing flavonoids in Passiflora species is needed in order to improve the quality assurance of the plant and derived extracts and phytomedicines. A survey on the profile of flavonoids and content of isovitexin in the leaves and fluidextract of P. alata through LC was carried out, comparing its chromatographic profiles with a commercial P. incarnata fluidextract. Also, the concentration of the total flavonoids of extracts and leaves according to phamarcopoeial photometrical methods was determined and discussed. The fluidextract of P. alata was produced in accordance with the Pharmacopoeia Helvetica method; the presence of isovitexin in both species (which have distinct chromatographic profiles) was evidenced, this being the major flavonoid compound in the P. incarnata (1.198 g%), but not in P. alata (0.018 g%) fluidextract. Only traces of vitexin could be observed in the P. alata, as well as the absence of the other tested flavonoids: orientin and swertisin (P. incarnata markers), hyperoside, rutin, hesperidin and clorogenic acid. The LC developed method was shown to be appropriated for the qualitative and quantitative analyses and for differentiate species, suitable to be applied to commercial sample analysis. The spectrophotometrical results of three different methods described for P. incarnata were not comparable, the best performance being the British Pharmacopoeia method.