Using SEM/EDX in the identification of GSR is a well-established technique applied in many laboratories. The automated GSR search system requires frequent and careful validation of the analytical procedure. As such, the Working Group “Firearms” of the European Network of Forensic Science Institutes (ENFSI) established a proficiency testing scheme for the detection and identification of GSR by SEM/EDX. This study, performed during 1999 through 2000, represents one such proficiency test. Participating laboratories determined the total number of PbSbBa-containing particles on the test samples using their own laboratory specific methods of automated GSR particle search and detection by SEM/EDX. In order to gain information on systematic errors within the obtained results, each laboratory also analyzed two samples containing synthetic GSR particles; one was supplied only with PbSbBa particles and one was contaminated with environmental particles. Overall, the proficiency test produced good results. There was demonstrated improvement regarding the total number of detected particles since the previous proficiency test. Table, references