The mechanical properties of cells are important for many cellular processes like cell migration, cell protrusion, cell division, and cell morphology. Depending on cell type, the mechanical properties of cells are determined mainly by the cell wall or the interior cytoskeleton. In eukaryotic cells, the stiffness is mainly determined by the cytoskeleton, which is made of several polymeric networks, including actin, microtubuli, and intermediate filaments. To study the mechanical properties of living cells at a subcellular resolution is of outmost importance to understanding the cellular processes mentioned above. One option is to use the atomic force microscopy (AFM) to measure the cell's elastic properties locally. By obtaining force curves, that is measuring the cantilever deflection while the tip is brought in contact and retracted cyclically, effectively the loading force indentation relation is measured. The elastic or Young's modulus can be calculated by applying simple models, like the Hertz model for spherical or parabolic indenters or Sneddon's modification for pyramidal indenters.