A study has been made on the mesomorphic properties of membrane preparations from normal and abnormal human red blood cells using a variety of physical techniques such as Fourier Transform Infrared Spectroscopy, Optical Microscopy and Differential Scanning Calorimetry. FTIR spectra of normal and abnormal ghosts confirmed that both have the same composition. Textures of the lyotropic treat phase were observed in normal ghosts. In addition, it was found that amphiphilic systems (such as membranes) may exhibit a nematic phase similar to that observed in thermotropics. DSC thermograms of normal ghosts showed that they go through several mesophases such as smectic and nematic. At the physiological temperatures, the membranes are in a lamellar smectic phase further lending support to the fluid mosaic model of cell membranes. Similar tests performed on membranes of thalassemic (abnormal) erythrocytes yielded no results that are similar to the liquid crystalline behavior of normal membranes.