  We investigate the prospects of detecting a Higgs pseudoscalar ($A^0$) in
association with a $Z$ gauge boson produced from bottom quark fusion ($b\bar{b}
\to ZA^0$) at the CERN Large Hadron Collider (LHC). A general two Higgs doublet
model and the minimal supersymmetric standard model are adopted to study the
discovery potential of $pp \to ZA^0 \to \ell \bar{\ell} b\bar{b} +X (\ell = e,
\mu)$, via $b\bar{b} \to ZA^0$ with physics backgrounds and realistic cuts.
Promising results are found for $m_A \alt 400$ GeV in a general two Higgs
doublet model when the heavier Higgs scalar ($H^0$) can decay into a $Z$ boson
and a Higgs pseudoscalar ($H^0 \to ZA^0$). We compare the production rates from
bottom quark fusion ($b\bar{b} \to ZA^0$) and gluon fusion ($gg \to ZA^0$) and
find that they are complementary processes to produce $ZA^0$ in hadron
collisions. While gluon fusion is the major source for producing a Higgs
pseudoscalar associated with a $Z$ boson at the LHC for $\tan\beta \alt 10$,
bottom quark fusion can make dominant contributions for $\tan\beta \agt 10$.
