Contemporaneous comovements of aggregated output time series between industrialized countries represent an important characteristic of the international business cycle and have already been well documented. This paper shows that a small open economy like Switzerland shares common short term GDP fluctuations with other European countries, independently of the specific definitions used for the common component. The serial correlation common feature (SCCF) hypothesis of ENGLE and KOZICKI (1993) and also the univariate and multivariate structural time series models (HARVEY, 1989) are presented and applied. Sharing common short-term economic fluctuations with other European countries has various economic policy implications for Switzerland. This last issue is commented in the light of the new commom monetary policy framework in the Euro area, since the beginning of 1999.