  In this paper we initiate the study of the total zero-divisor graphs over
commutative rings with unity. These graphs are constructed by both relations
that arise from the zero-divisor graph and from the total graph of a ring. We
characterize Artinian rings with the connected total zero-divisor graphs and
give their diameters. Moreover, we compute major characteristics of the total
zero-divisor graphs of the ring ${\mathbb Z}_m$ of integers modulo $m$ and
prove that the total zero-divisor graphs of ${\mathbb Z}_m$ and ${\mathbb Z}_n$
are isomorphic if and only if $m=n$.
