Microtubules are long, hollow, stiff polymers that extend throughout the cytoplasm. They are involved in such diverse functions as governing the location of membrane-bounded organelles and chromosome separation during mitosis. The basic structural unit is tubulin, which is a heterodimer consisting of two closely related and tightly linked globular polypeptides called α and β-tubulin. Alternating α and β tubulin subunits form protofilaments, 13 of which bundle around a central core to form microtubule. The detailed structures of cytoplasmic microtubules have been studied extensively using various electron microscopic techniques. As microtubules are dynamic structures in constant transitions between growing and shrinking phases, it would be extremely interesting to investigate the structural organization of the subunit tubulin molecules in a buffer close to physiological conditions. With its high resolution and ability to image in fluid, atomic force microscope (AFM) makes it possible to study the biological structures in a native environment.