We report on the production and characterization of a high-entropy alloy in the refractory Zr-Nb-Ti-V-Hf system. Equiatomic ingots were produced by arc and levitation melting, and were subsequently homogenized by high-temperature annealing. We obtained a coarse-grained, single-phase high-entropy alloy, with a homogeneous distribution of the constituting elements. The phase is a chemically disordered solid solution, based on a bcc lattice with a lattice parameter of 0.336(5) nm.Keywords: High-entropy alloys, multicomponent solidification, microstructure, transmission electron microscopy (TEM) High-entropy alloys (HEAs) constitute a new field in materials science, dealing with alloys containing five or more metallic elements in equiatomic or near-equiatomic composition, which solidify as a solid solution on a simple crystal lattice [1,2]. In these materials topological order and chemical disorder are present at the same time. This apparent discrepancy classifies them between conventional crystals, which possess chemical as well as topological order, and metallic glasses, which are disordered in all regards. A prerequisite for the fundamental understanding of the consequences of these salient structural features for the physical properties, is the development of high-quality materials and their meaningful characterization. Experiments carried out on such well-defined samples can then readily be interpreted in terms of intrinsic materials properties, without misleading stray influences by secondary phases, undetected ordering, etc. To date, HEAs based on fcc, bcc and hcp crystal structures have been observed, for all of which equiatomic single-phase representatives exist, e.g. fcc FeCoCrMnNi [2], bcc ZrNbTiTaHf [3], and hcp HoDyYGdTb [4]. In the present paper we describe the production and characterization of a HEA in the system Zr-Nb-Ti-V-Hf. Our motivation is to explore an alternative bcc single-phase material, closely related to the well-known refractory HEA ZrNbTiTaHf, and make it available for comparative experiments. Two earlier publications relate to the Zr-Nb-Ti-V-Hf system, none of which however forestalls our results presented here. Li et al. calculated mechanical properties of a bcc ZrNbTiVHf HEA by ab-initio alloy theory [5]. In this purely theoretical work, the competing Laves phases were not taken into account, and the authors did not check whether or not a bcc ZrNbTiVHf phase forms in reality. Gao et al. [6] described the six-element system Zr-Nb-Ti-Ta-Hf-V but did not investigate or discuss the Zr-Nb-Ti-V-Hf subsystem. On the long run, we strive toward the development of a single-crystal growth route for a bcc HEA. To date successful single-crystal growth was only reported for fcc HEAs [7] and bcc/B2 two-phase materials [8]. The known bcc HEA ZrNbTiTaHf has a very high melting temperature (2249 °C calculated as weighted average of the constituting elements [3]), which essentially limits the applicable growth techniques to crucible-free approaches. We have previously