Thin films of m-xylene have been prepared by a plasma polymerization method using a capacitively coupled reactor. The structural investigation of the plasma-polymerized m-xylene (PPm-X) films has been carried out using polarized light microscopy and IR spectroscopy. Films are smooth and pinhole free and observed to be structurally different from m-xylene. The a.c. conductivity, dielectric constant, and dielectric loss tangent have been measured. The observed data suggest that on heat treatment the PPm-X film stabilizes. The dielectric behaviour of the films is discussed in the light of the observed data.