Let (R, M) be a local (Noetherian) ring with completion R such that t
he maximal ideal M is regular (i.e. Al contains a non-zerodivisor.) Th
is note shows that R contains a depth one prime divisor of zero (i.e.
there exists a prime ideal q in R such that q is an associated prime
of R with height(MR*/q) = 1.) if and only if M is an associated prim
e divisor of every regular ideal I of R contained in a proper principa
l ideal.