The Magellanic Clouds, consisting of the LMC, the SMC and the Bridge offer an ideal laboratory for studying cluster formation in a lower metal abundance environment at an unrivaled closeness to us among external galaxies. It is known that very young populous clusters like R136 are still being formed in the LMC, where populous clusters include more than 10000 stars tightly gravitationally bound. In this talk, I will present mm and sub-mm CO observations of the Magellanic molecular clouds obtained with NANTEN, SEST, and ASTE at spatial resolutions of 5–50pc. I will then use these CO data to identify the parent cloud cores for populous clusters and discuss the cluster formation by comparing the cloud properties with those of the Milky Way.