Metabolomic analysis by liquid chromatography high-resolution mass spectrometry results in data sets with thousands of features arising from metabolites, fragments, isotopes, and adducts Here we describe a software package, Metabolomic Analysis and Visualization ENgine (MAVEN), designed for efficient interactive analysis of LC-MS data, including in the presence of isotope labeling The software contains tools for all aspects of the data analysis process, from feature extraction to pathway-based graphical data display To facilitate data validation, a machine learning algorithm automatically assesses peak quality Users interact with raw data primarily m the form of extracted ion chromatograms, which are displayed with overlaid circles indicating peak quality, and bar graphs of peak intensities for both unlabeled and isotope-labeled metabolite forms Click-based navigation leads to additional information, such as raw data for specific isotopic forms or for metabolites changing significantly between conditions Fast data processing algorithms result in nearly delay-free browsing Drop down menus provide tools for the overlay of data onto pathway maps These tools enable animating series of pathway graphs, e g, to show propagation of labeled forms through a metabolic network MAVEN is released under an open source license at http //maven princeton edu