In this work, the spin-averaged mass spectra of heavy quarkonia (cc and bb ) in a Coulomb plus quadratic potential is studied within the framework of nonrelativistic Schrodinger equation. The energy eigenvalues and eigenfunctions are obtained in compact forms for any -value using Nikiforov-Uvarov method. The obtained results are used to produce potential parameters (a, b , and o ) for the charmonium and bottomonium systems, from which then their full mass spectra are determined. The obtained values are compared with the available experimental results. The predictions from our model are found to be in good agreement with the experimental results. As a side result, the Hydrogen atom known spectrum is recovered