This research project develops and applies econometric tools to perform online break-point detection (monitoring) in a Johansen (1995)-type vector error correction model. To monitor structural changes the break-point detection procedures of Seo (1998) and Hansen and Johansen (1999) are planned to be adapted to the monitoring case. The monitoring tools are applied to investigate the stability of money demand and some arbitrage parities discussed in finance literature. The tools are made available in an R-package.