This paper is focused on mix design of PVA (polyvinyl alcohol) fiber reinforced lightweight concrete (FRLWC). By designing mix compositions, a high performance composite can be produced with a small amount of short fibers. In this study, we have successfully developed high performance fiber reinforced lightweight concrete (HPFRLWC) that shows high flexural strength, high flexural ductility, and excellent toughness. At the same time, the densities of the HPFRLWC can be made between 0.8 and 1.6 g/cm(3), representing 35-75% reduction from normal weight concrete. For ultra lightweight composites, excellent ductility can be maintained at the expense of strength. This paper provides a framework for the mix design of HPFRLWC in order to achieve much improved tensile performance of otherwise brittle material. (c) 2006 Elsevier Ltd. All rights reserved.