The present study presents two methods for measurement of Ang peptides in cellular lysate or tissue homogenates: HPLC-UV and Mass Spectrometry (MS) using as a gold standard the Radioimmunoassay (RIA). For the quantification of Ang peptides, we did the extraction and purification of peptides using a column Sep-Pak C-18 previously activated, after the sample extracts were injected onto the analytical column of the HPLC or Mass Spectrometer Systems (MSS). HPLC-UV detection was performed at 214nm, with sensitivity setting of 0.010 AUFS. Standard curves were established for each peptide and all peptides were analyzed together each day to obtain the retention time for the day. The samples were analyzed also on a system composed of a micromass plataform Spectrometer-HPLC, photodiode array detector, and a Compaq Workstation. The peptides were loaded on a reverse-phase HPLC column Waters Nova-Pak C18, solvent A 0.1% TFA/H₂O, and B 0.1% TFA in acetonitrile/H₂O at a flow rate of 0.4 ml/min, detection in a mass range of 500-3930 daltons. The RIA was the gold standard method. Analytical recovery of 90.0% to 138.0% was observed throughout the assay’s linear range (5-500.0 ng/ml) when we used MS. The lower limit of quantification was set at 1.0 ng/ml, and the sensitivity was analyzed in replicates of 1.0 ng/ml, presenting a CV of 9.0%. The inter-assay precision ranges from 9% to 19% and the intra-assay from 1.8% to 9.2%. Peptide analysis using only HPLC presented for intra- and inter-assay range from 2.6 to 7.0% and 2.0 to 9.2, respectively. Exist a linear relationship between peak height and peptide amount injected with an analytical recovery of 90.0% to 102.0%. Both methods presented the same concentration levels for the samples analyzed differing from RIA, but presented correlation coefficients of 0.99 enter methods. Both methods are sensitive, precise and accurate to measure Ang peptides when applied with the correct extraction procedure to eliminate interferences. Supported by FAPESP.