Two types of quadrilateral transition elements based on the Mindlin-Reissner plate theory are presented for the adaptive mesh refinement in the plate bending problem. The first type of transition element, designated as the conforming transition element, has piecewise linear folded side(s) which preserves the interelement compatibility when connected to refined four-node elements, and has been improved by construction of the substitute shear strain fields. The other type of elements, designated as the nonconforming transition element, can have curved side(s) and has been improved by the selective addition of nonconforming displacement modes. Numerical examples are presented to evaluate the performance of proposed elements. It was shown that the nonconforming model produces a smoother stress distribution than the conforming model does, even though the nonconforming model is not compatible along the interelement boundaries. It was also shown that both of the transition elements can be effectively used for the adaptive mesh refinement and the discretization error by nonconforming model reduces more rapidly than the conforming model. (C) 1997 Elsevier Science Ltd.