Viscoelastic and phase behaviors of Na-type gellan were investigated. The complex shear modulus of aqueous gellan solutions was monitored as a function of concentration, temperature, and molar mass. At relatively low concentrations, the loss shear modulus, G '', increased steeply at a certain temperature upon cooling, which was attributed to helix formation. Above a certain concentration, a steep increase and then gradual decrease of G '' was observed. The decrease of G '' was significant and is considered to be due to anisotropic phase formation, judging from the macroscopic phase separation into upper isotropic and lower anisotropic phases of a gellan solution kept quiescently in a vial. Polarized light microscopy produced an image showing a nematic liquid crystalline phase. Although gel formation was not observed when gellan alone was used in the present study, the gellan formed a gel in the presence of an appropriate amount of salt.