ABSTRACT: Yemen has an appreciable amount of scoria aggregate, but a very small proportion is used as cement additionsby local cement factories in blended Portland cement production and very rarely as aggregates in to the productionof lightweight blocks. Scoria aggregates are widespread in and around the volcanic cones present in Sana’a-Amranvolcanic field. This paper presents the results of evaluation of engineering properties of natural scoria, collected fromAl-Haweri volcanic cone, NW Sana’a, Yemen as lightweight aggregate. Chemical composition and petrographicalcharacteristics of scoria were determined. The physical properties of the scoria aggregate such as flakiness andelongation indices, specific gravity, water absorption, unit weight, clay lumps and materials finer than 75µm gaveacceptable results, but the gradation indicated it would need to be processed before use in a mix. The porosity ishigh, 60.79%. The Los Angeles abrasion and the aggregate crushing values are higher than the limits of ASTM andBS specification, but the aggregate impact value is close to the upper limits of BS specification. The soundness iswithin the ASTM specification limits. Therefore, it can be concluded that scoria aggregates can be used to producestructural concrete and masonry blocks with a relatively low density. The scoria aggregates satisfied the requirementsof lightweight aggregate for structural concrete and masonry blocks purposes.