Pyrococcus furiosus PF2050, a putative uncharacterized protein, was overexpressed in Escherichia coli, purified and crystallized at 298 K using 2-methyl-2,4-pentanediol as the precipitant. X-ray diffraction data were collected to a resolution of 1.56 Å at 100 K using synchrotron X-rays. The crystal was found to belong to space group P2(1), with unit-cell parameters a = 41.76, b = 66.43, c = 46.38 Å, β = 96.62°. The asymmetric unit contained one subunit of PF2050, with a crystal volume per protein weight (V(M)) of 2.21 Å(3) Da(-1) and a solvent content of 44.41%.