A long life-time (>0.3 ms) quantum degenerate molecular Rydberg plasma is generated in the high-density region of a pulsed supersonic jet expansion by two-colour resonant excitation of nitric oxide (10%) in neon (5bar) into the high-n Rydberg threshold region close to the ionization limit. For the plasma densities of < 1016 cm–3 reached in our experiments the electrons should become quantum degenerate, i.e. the electron de Broglie wavelength becomes larger than the Wigner-Seitz radius a relevant to describe the mean distance between the particles. Considering the well-known properties of pulsed supersonic jet expansions and textbook plasma physics, the Fermi energy  EF = (3p2)2/3ne2/3h2/8p2me becomes bigger than the thermal energy kT .