摘要:Along with the increasing demand for habitation in Indonesia, the need for concrete as the most favourable housing material is escalating. Oil Palm Shell (OPS) as coarse aggregate material is a possible alternatives material in concrete mix proportions. This possible choice of material not only can fulfil the requirements of the materials, but is also capable of reducing the problem of OPS waste in Indonesia. As OPS concrete compressive strength in previous studies in laboratory is in the range of 20-23 MPa, studies on larger elements of structure become interesting. This research presents flexure behaviour of lightweight concrete beams using OPS replacing natural coarse aggregates under four-point loading application. OPS is firstly pre-treated using hot water at 50°C based on previous research. In this study, a series of tests was conducted on two samples of identical beam with dimension of 15×25×300 cm. This size represents the typical dimension of beam used in two-storey houses in Indonesia. Mechanical response due to bending that occurs in OPS lightweight concrete beam is presented. Observation on the beam is emphasised on the pure bending area.