Abstract: A new stiffened plate element is constructed to investigate the geometrically nonlinear behavior of arbitrarily stiffened laminated composite plates. In this model, the stiffener can be placed at anywhere within the plate element and oriented in any direction. The Von-Karman kinematic relations of the plate and stiffener are considered. The transverse shear deformation effect is included by use of Mindlin-Reissner first-order shear deformation theory. This new stiffened plate element has the same degree of freedom as regular plate elements. The results obtained by the proposed method indicate that good agreement with available values can be reached with relatively coarse mesh and less computational time.