Short chain branched (SCB) polyolefins as a model of metallocene ethylene/alpha-olefin copolymers were simulated by Monte Carlo (MC) and molecular dynamics (MD) methods. Melt density, which was evaluated by MD in the isothermal-isobaric ensemble (NPT-MD), slightly increases with the SCB content. A mix of different MC moves was adopted and connectivity-altering moves, such as end-bridging, were modified in order to incorporate the branches into the simulation. This MC simulation strategy performed very well in equilibrating molten SCB copolymers at all length scales. The chain size and local packing in the melt, as obtained from the MC simulations. are discussed. At given backbone length, chain size, as quantified by the radius of gyration, decreases with the number of branches. On the other hand, the presence of short branches leads to a less effective intermolecular local packing in the melt. Rheological properties of the copolymers are, discussed based on a mapping of the Monte Carlo atomistic simulations on the packing length model, and compared with experimental results. it general, Pod agreement with experimental results is found.