The microwave spectrum of propargyl selenol, HC CH2SeH, has been investigated in the 19-80 GHz spectral range at -30 degrees C. The spectra of five isotopologues of one conformer, which has a synclinal conformation for the C-C-Se-H link of atoms, were assigned. This conformational preference allows for the formation of a weak intramolecular hydrogen bond between the hydrogen atom of the selenol group and the it electrons of the triple bond. This hydrogen-bonded conformer is at least 5 kJ/mol more stable than the rotamer having an antiperiplanar conformation for the C-C-Se-H chain. The microwave spectrum clearly shows that the hydrogen atom tunnels between the two mirror-image synclinal forms, but it was not possible to determine the tunneling frequency. The microwave study has been augmented by quantum chemical calculations at the MP2/aug-cc-pVTZ and B3LYP/aug-cc-pVTZ levels of theory. These calculations predict rotational and centrifugal distortion constants that are in good agreement with the experimental counterparts but predict a far too small energy difference of approximate to 1.5 kJ/mol for the energy difference between the antiperiplanar and synclinal forms. The conformational properties and internal hydrogen bonding of HC CCH2SeH are compared with similar properties of other selenols, which are stabilized by intramolecular hydrogen bonds.