A keyword spotting system, developed at Brno University of Technology, Faculty of Information Technology, will be presented. This system is designated mainly for detecting keywords in long speech records. Keywords are modeled with triphone Hidden Markov Models. The models were trained on Czech SpeechDat-E speech database [1]. For recognition, a Modified Viterbi algorithm [2] is used. New procedure to determine optimal thresholds for keyword acceptation, based on statistical analysis of false acceptations and false alarms on a large database, was developed. All components of the system are in-house, but the models are compatible with the widely used HTK toolkit. The system is running on MS-Windows. A public evaluation version for Czech will be available from http://www.fit.vutbr.cz/research/groups/speech/sw.html [1] Heuvel Henk, Boudy Jerome, Bakcsi Zoltan, Cernocky Jan, Galunov Valerij, Kochanina Julia, Majewski Wojciech, Pollak Petr, Rusko Milan, Sadowski Jerzy, Staroniewicz Piotr, Tropf Herbert: SpeechDat-East: Five multilingual speech databases for voice-operated teleservices completed, In: Proc. EUROSPEECH 2001, Aalborg, 2001 [2] J. Junkawitsch, L. Neubauer, H. Hoege and G. Ruske: A new keyword-spotting algorithm with pre-calculated optimal thresholds, Proc. Intl. Conference on spoken language processing ICSLP, 1996 Related link: http://www.fit.vutbr.cz/research/groups/speech