  We present near-IR narrow-band continuum-subtracted images in the H$_2$
$2.122\mu$m, and Br$\gamma$ $2.166\mu$m emission lines for a sample of 15
bipolar planetary nebulae. H$_2$ emission was definitely detected for most of
the objects in this sample (13 out of 15). The very high H$_2$ detection rate
supports the idea that bipolar planetary nebulae have important reservoirs of
molecular material and offer suitable physical conditions for the excitation of
H$_2$. The strength of the H$_2$ emission and the H$_2$/Br$\gamma$ flux ratio
are found to correlate with the morphology of the bipolar nebulae observed.
Bipolar PNe with broad and bright rings exhibit stronger H$_2$ emission than
bipolar PNe with narrow twists. High-quality (sub-arcsec) [N~{\sc ii}] and
H$\alpha$ optical images have been used to compare the distribution of the
ionized and molecular material. The H$_2$ emission lies just outside the
optical [N~{\sc ii}] emission zone.
