Background: Identification of detected compounds in untargeted LC/MS profiling is a common bottleneck in metabolomics. The CASMI contest challenges mass spectrometry experts and algorithm developers to evaluate how reliable their methods derive molecular formulae and structures from blinded mass spectral data.Objective: The application of the MAGMa software to solve the CASMI 2014 challenges is described. Methods: MAGMa was used to automatically retrieve candidate molecular structures from the HMDB and PubChem chemical databases, based on MS1 precursor m/z values, and to provide a score indicating how well they explain the accurate MS2 spectra. Results: For 40 out of 48 challenges, candidates with the correct molecular formula were ranked on top. For 22 out of 42 challenges the top-ranked candidate also represented the correct chemical structure and in 9 other cases the correct molecule was ranked in the top 10. Conclusion: Advantages and limitations of the approach and consequences with respect to retrieving and scoring of the correct candidates are discussed.