  In this paper, we will examine the problem of violation of causality in
$f(R,T)$ modified gravity, where $R$ is the Ricci scalar and $T$ is the trace
of the energy-momentum tensor $T_{\mu\nu}$. We investigate the causality
problem in two special cases, in the first we consider the matter content of
the universe as a perfect fluid and in the second case, the matter content is a
perfect fluid plus a scalar field.
