Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes both of carboxylation and oxygenation of ribulose-1,5-bisphosphate (RuBP) and is present in almost of autotrophic organisms. It is one of enzymes with the fewest catalytic efficiency in nature, whose activity should be enhanced for practical utilization. Structural data might be used for improving the catalytic activity of Rubisco. In this study, the recombinant Rubisco large subunit (RbcL) protein from Hydrogenovibrio marinus (HmRbcL) was expressed in Escherichia coli and purified. The purified HmRbcL protein was concentrated and crystallized from the precipitant composed of 0.1 M Tris-HCl (pH 8.5) and 1.5 M Ammonium phosphate dibasic. X-ray diffraction data was collected to 2.65 A resolution. The crystal belongs to the primitive monoclinic P21 space group with unit-cell parameters a = 74.47 A, b = 57.10 A, c = 126.09 A, α = γ = 90°, and β = 102.85°, and includes two HmRbcL molecules in the asymmetric unit.