We present the results of a systematic search of Beat Cepheids (BC) in the Magellanic Clouds from the EROS-2 database. Observations were carried out on the MARLY telescope (ESO La Silla, Chile) between July 1996 and March 2003. A specific pipeline was developed to extract periodic light curves from the photometric data obtained with the PEIDA package (Ansari, 1996VA.....40..519A). Two different populations are identified in each Cloud: the BCs pulsating on the fundamental and first overtone modes (FO/F objects) simultaneously, and those pulsating on the first and second overtones (SO/FO objects). A Fourier analysis was performed on each light curve. We derived lower, higher and mean values of metallicities for the FO/F objects, using linear nonadiabatic convective stellar models.