We discuss how one can identify CP violation (and conservation) in
multi-Higgs-doublet potentials. After a brief review of CP violation
in the 2HDM, we refer to the fact that for NHDM with $N \geq 3$ the well
known methods useful in the case $N = 2$ have not been generalized
in order to provide a set of well defined necessary and sufficient
conditions for CP conservation. We then present a simple method,
proposed by the authors, to be used in such cases.
Two non-trivial examples based on an $S_3$-symmetric three-doublet model
are analyzed by means of this new method.