One of the most successful approaches for the identification of small molecule unknowns has been GC-MS analysis combined with mass spectral library searching. Unfortunately, a similarly useful tool has not yet presented itself in the field of LC-MS. This is primarily due to the fact that the soft ionization techniques used with LC-MS generate mass spectra possessing very few ions, making library searching difficult. A more practical approach for identification of unknowns by LC-MS is to use complimentary techniques such as accurate mass measurements combined with additional structural information, either from NMR or MSn experiments. For cost effective measurement of accurate mass, time-of-flight mass spectrometry (TOFMS) has become a useful tool. For applications involving non-target analyte screening, TOFMS also offers high �full scan' sensitivity and wide dynamic range for detection of large numbers of analytes over a wide concentration range. In this work, efforts towards the rapid identification of unknowns using TOFMS accurate mass data, automated peak finding, and novel library searching tools will be described. The scope and limitations of this approach will be evaluated and successful application of this methodology to the identification of unknown environmental contaminants will be presented.