Supernova remnants (SNRs) mark the end point of stellar evolution. As they release tremendous amounts of kinetic energy and freshly-produced heavy elements into the interstellar medium (ISM), and accelerate cosmic-rays, SNRs are a key component of the chemical and thermodynamical evolution of the ISM in galaxies. X-ray emission is ubiquitous in SNRs, as their shocks heat the SN ejecta and ambient medium to multi-million degree temperatures. X-ray observations are thus an excellent tool to measure properties of SNRs (e.g. age, explosion energy, or type of supernova progenitor) and to probe the origin of the hot phase of the ISM.
However, studies of SNRs in general, and of their X-ray emission in particular, are hampered in our own Galaxies by distance uncertainties and large absorption columns. On the other hand, the Magellanic Clouds offer ideal targets hosting a large population of SNRs that were surveyed recently with large XMM-Newton programmes. In this talk, I will showcase results from the X-ray study of the SNR populations in the LMC and SMC, and present the recent discovery of a new population of iron-rich SNRs, which are the most evolved remnants of type Ia supernovae.