NGC 5128 is one of the few elliptical galaxies in which resolved stellar populations can be studied and compared to other population tracers like PN and globular clusters. I will present the results of a long-term monitoring of the red giants in NGC 5128 with FORS1 and ISAAC instruments at the ESO VLT. This study has revealed a large number of bright red giants that show long period and large amplitude variability characteristic of Mira AGB stars. A comparison is made between their properties and those found in old stellar populations like Galactic globular clusters and Galactic bulge as well as with intermediate-age Magellanic Cloud long period variables. While the majority of the LPVs in NGC 5128 share similar periods and near-IR colors with Galactic bulge variables, some ~10% of LPVs probably have more massive and thus younger progenitor stars.