A cultured endothelial cell on a substrate was modeled as a homogeneous, incompressible, isotropic, hyperelastic structure consisting of the cell cytoplasm and nucleus and the substrate. Finite element analyses were used to evaluate the stress/strain distributions in the cell when stretch was applied to the substrate. The results reproduced experimental results reported in the literature. The strain component in the stretch direction decreased as the position in the cell became higher. The rate of decrease in the strain with height depended on the shape of the cell. This means that the cellular dimensions are required to evaluate the measured cellular deformation adequately. The analysis also showed that our model had a region with the same decrease in strain as that reported in the literature. We could also predict the orientation of stress fibers by using the deformation data obtained from the finite element analysis of the cell.