Coffee is one of the most consumed beverages in the world, with Coffea arabica (arabica coffee) and Coffea canephora (conilon variety of robusta coffee) the species most commercialized. Coffee is composed by carbohydrates, proteins, lipids, chlorogenic acids, alkaloids and others. Caffeine (C8H10N4O2) belonging to methylxanthines group is considered an alkaloid stimulant, used in drugs and energy drinks, and is present in high concentration in robusta coffees. Trigonelline is found in high content in arabica coffees, also belongs to alkaloids class and with sensory and nutritional importance.1 In order to evaluate the coffee quality, a chromatographic method was developed and validate for simultaneous quantification of caffeine and trigonelline in roasted commercial coffee. The study of the sixty samples of commercial coffee obtained from markets in the Paraná state, Brazil, was performed. The samples have been prepared following the ISO 20481:2008 method2, with some modification: 0.5 g of commercial coffee was weighed on a dry basis and 2.0 g of magnesium oxide and 100 mL of water were added. The samples were homogenized and heated at 90°C for 20 minutes. The extract was filtered and the supernatant analyzed by UPLC-UV-DAD. The separation was performed using a column Acquity UPLC® BEH C18 (2,1 x 50 mm; 1,7 µm; Waters). The solvent system used a mixture of H2O (A) and ACN (B), and the following gradient was applied: 1% to 99% B in 3 min. Elution was carried out at a flow rate of 1 mL min-1, at 40 C. Compounds were detected at 272 nm. The chromatographic method was validated according to ANVISA (RDC 899/2003)3. The parameters specificity, selectivity, precision, linearity, limit of detection and quantification, accuracy and robustness were analyzed. The results were submitted to ANOVA, principal component analysis (PCA) and hierarchical cluster analysis (AAH) using the Statistica 8.0 program. The UPLC-UV-DAD method showed to be selective, linear, precise, accurate and robust and presented faster analysis of the compounds of interest compared with literature data,4 with retention times of trigonelline and caffeine of 0.33 and 0.93 minutes, respectively. Variations in caffeine and trigonelline concentrations were different for arabica and conilon coffee within 5% level of significance applying Tukey test, with the values founded agree with amounts reported in the literature. With score plot and loadings from the PCA was possible to discriminate different types of coffee by the levels of caffeine and trigonellin; this study allowed grouping the different types of coffee samples, distinguishing them by their caffeine and trigonelline content.