The present paper is concerned with the derivation of the Einstein's formula of equivalence of mass and energy, E = mc^2 , from the universal uncertainty relations. These relations are a generalization of the original uncertainty relations developed by Werner Heisenberg in 1927. Thus, this approach unifies two of the most important laws of physics as provides the proof of a) the quantum mechanical nature of the above formula, and, b) the correctness of the universal uncertainty relations that I found in 2012.