A low-order thick and thin plate bending element is derived using bilinear approximations for the transverse deflection, the two rotations and the thickness change. The stress-strain relationships from three-dimensional elasticity are used without any modifications. In order to avoid locking and to improve the accuracy of the results eight enhanced strain modes are used. For an efficient implementation of the mixed element, orthogonal stress and strain functions are utilized. Although the element is a low-order finite element the numerical results for a series of standard test problems are excellent. Copyright (C) 2001 John Wiley & Sons, Ltd.