Foaming of thermoplastics is a technically valuable route to efficiently use materials. Beam theory provides sound arguments for placing materials preferentially away from the neutral axis of a structure to preserve or even increase its bending stiffness with respect to a comparable Soild (unfoamed) reference. Practical applications of this concept can be found in rigid packaging (thermoformed containers and blow molded bottles) as well as in flexible packaging structures (blown and cast films). Appropriate resin selection is key to foaming because processing conditions need to be often modified to optimize pressure drop rates and cell formation. Empirical experience shows that among all polyethylene types LDPE is the most amenable to foaming. This has been traditionally linked to the high melt strength common to all LDPE types. However, as will be illustrated throughout this work, different processing conditions could lead to seemingly counterintuitive results in which resins with low melt strength lead to very fine and regular cell structures. The present investigation analyses a series of LDPEs and LLDPEs, spanning a wide range of viscosities in the context of their foamability. That is their ability to produce small and uniform foam cells. All materials are processed in comparable ways through state of the art blown film equipment modified for direct injection of supercritical fluid using Mucell® process technology. This foaming process has proven to be successful at reducing material consumption in rigid and flexible packaging applications. A series or rheological measurements spanning shear rheology and compliance have been carried out for the complete range of polyethylenes analyzed. Attempts to establish a correlation between these measurements and foaming performance are presented, making emphasis on different processing conditions unique to each resin group.