Psidium cattleianum presents high levels of phenolic substances, it has several antioxidant properties and its seeds are the by-product which contain a considerable amount of bioactive compounds. The aim of this study was to identify phenolic compounds present in the Araçá seeds demonstrating its potential as a by-product. One fraction of seeds was directed to moisture analysis and other were dried and ground. 5 mL of 50 % ethanol solution to 0.5 g of the ground seed were sonicated for 30 min, centrifuged and the supernatant was filtered through membrane filter, then 20 µL was injected on a high-performance liquid chromatography, equipped with a diode array detector with a coupled mass spectrometer (HPLC-DAD-MS) performed with a C18 column (250 x 4.6 mm, 5 µm, NST), the mobile phase was composed by water and methanol with 0.1 % of formic acid and flow rate was at 1.2 mL min-1. UV detection was at 372 nm. Compounds identification was performed according to it molecular weight and fragmentation mass (m/z). In the red Araçá seeds (36.42 % of moisture) an ion at m/z 437 was identified as catechin hexoside; ions at m/z 463, 433 and 301 indicated the presence of quercetin-hexoside, quercetin-pentoside and quercetin. In the case of yellow Araçá seeds (40.87 % of moisture) ions at m/z 319 and m/z 163(bp) in were identified as 3,4-di-O-(E)-p-coumaroylquinic acid. Also were observed ions at m/z 205 and 198 corresponding coumaroyl tartaric and syringic acids. An organic acid fragment also identified at m/z 97 as isopropyl citrate. Thus, it was observed that the seeds contain a wide range of phenolics compounds, mainly flavonoids, it most abundant in the red Araçá.