The broadening and shift of four spectral lines arising from the 2p53p-2p56s transitions of neon emitted from a low pressure glow discharge in pure neon and a neonhelium mixture have been measured. The values of the pressure broadening and shift coefficients are determined. The results are interpreted in terms of the impact theory assuming the Lennard-Jones potential. Results obtained in this work indicate that the Lennard-Jones potential cannot describe adequately the broadening and shift of the spectral lines under investigation.