  We present high angular resolution VLA and BIMA observations of NH$_3$,
HCO$^+$, HCN and SO molecular emission and 1.4, 3.5 and 7 mm continuum emission
toward the exciting source of the HH~80-81 system. This object is one of the
few massive protostars known to be driving a collimated outflow. We report the
first detection of SO 5$_5$--4$_4$ molecular emission toward the exciting
source of HH 80-81, suggesting that this transition may be a good tracer of
molecular gas near massive protostars. We also detected toward this source dust
continuum emission at 1.4 and 3.5 mm. From the SO molecular emission and the
dust emission we roughly estimated that the molecular mass associated with the
circumstellar surroundings of the exciting source of the thermal jet is in the
range 1 -- 3 M$_\odot$. Weak and broad (2,2) ammonia emission was also found in
the direction of the jet suggesting the presence of small amounts of molecular
gas at high temperatures ($>$ 50 K).
  The VLA observations show the presence of three ammonia components toward the
HH 80-81 region. The brightest component peaks at $\sim8^{\prime\prime}$ to the
NE of the thermal jet and is associated with the H$_2$O maser spots in the
region. A second ammonia clump is located about 25$^{\prime\prime}$ to the NE
of the jet and is associated with class I methanol masers. The third ammonia
component is located 1$^\prime$ to the south from the thermal jet and may be a
molecular core yet without stellar formation. The BIMA observations show that
the strongest emission in the HCO$^+$ and HCN lines originate close to the
H$_2$O maser, and cover the same spatial region and velocity range as the
brightest ammonia component.
