Polarized transmitted light observation was used to examine the Krafft point temperature of cesium dodecylsulfate (CsDS) in water over a wide range of concentrations. CsDS shows an elevated Krafft temperature compared to that of sodium dodecyl sulfate (SDS). Unlike SDS, the CsDS solubility temperature remains virtually constant at high concentration. Also, the stable birefringent liquid crystal appears at a much lower concentration for CsDS than for SDS, and the concentration window of its coexistence with isotropic micellar solution is broader.