Carl Johan Hegerin och Jonas Gustafsson Systematic FX-trading Abstract The foreign exchange(FX) market is known as one of the most liquid markets in the world. It is open 24 hours a day 7 days a week and has a daily turnover of $ 1.9 trillion. The aim of this study has been to investigate how to proceed when building a Trading System for the FX-market. The study incorporates characterizing FX rate behavior and suggesting statistical methods to model the behavior with profit generating in mind. The data used is high frequency 1 min EUR based crossrates sampled during 2004.1-12 and 1 min Eur/Usd sampled during 2002.1-2004.12. The study uses theory involving Stochastic Differential Equations as well as filter techniques using the Kalman Filter. The study is focused upon the progressive work of the building of a trading strategy and gives a view of the problems faced.