Compared to fiber reinforced concrete (FRC), self-compacting concrete (SCC) is a relatively new type of concrete with high flowability and good cohesiveness. It offers very attractive economical and technical benefits, which can be further extended when combined with FRC. In this article two different types of steel fibers were used, in combination, and the effects of fiber inclusion on the workability of hybrid fiber reinforced self-compacting concrete (HFR-SCC) is studied. The effects of fibers are quantified based on the fiber volume, length, and aspect ratios of the fibers. It was concluded that in addition to the above-mentioned quantifiable three properties, other properties of fibers such as shape and surface roughness are also found to be important but they cannot be quantified at this stage. (c) 2005 Elsevier Ltd. All rights reserved.