Focused ion beam secondary ion mass spectrometry (FIB-SIMS) is a material identification technique that combines the high spatial resolution of FIB with the high elemental sensitivity of SIMS. FIB-SIMS has generated important elemental analysis data in the form of ion images for a wide range of applications including minerals, metal alloys, semiconductors, and biological materials. Quantitative imaging is possible by analysis of cross sections of reference samples in which elements are ion implanted or present at known concentrations in the substrate of interest. Elemental information on complex materials can be obtained using the high mass resolution capability of magnetic sector or time of flight analyzers. This technique will provide improved elemental sensitivity as new methods for enhancement of secondary ion yields can be developed.