Peptide quantification is a pre-requisite in many areas of proteomics and peptidomics. For example, methods to separate peptides based on chromatography or electrophoresis, require accurate loading of peptide mixtures (e.g., from tryptic digests) to achieve the required sensitivity, without overloading. There are a number of colorimetric peptide assays such as ninhydrin, Lowry and BCA but these methods often lack the required sensitivity particularly where samples are precious. Amino Acid Analysis is often regarded as the ‘gold standard’ but the method is relatively expensive and is outsourced in many laboratories making it inconvenient. Epicocconone is a natural product that spontaneously conjugates to amine residues in proteins and peptides yielding an intensely fluorescent red product. This change in the fluorescence properties provides a novel approach for the sensitive quantification of proteins and peptides in solution, gels and blots. Covalent binding to proteins is only stable in acid (pH 2.4) and epicocconone can be removed by changing pH. Reversible binding renders peptides amenable to analysis by mass spectrometry, Edman-based sequencing, and functional assays. We report here a fast, sensitive and robust fluorescence based peptide quantification method using FluoroProfile (Sigma-Aldrich), an epicocconone-based reagent kit originally configured for protein quantification. FluoroProfile is sensitive enabling quantification of <100ng / mL of peptide and has a linear dynamic range of >4 orders of magnitude. The assay takes 1 hour and can be performed in a standard 96 well plate read using a fluorimeter or plate reader. Reversible binding of FluoroProfile means that the same samples used for peptide quantification can also be used for subsequent analysis, for example by mass spectrometry.