Crystals of a 40 kDa p-cresolyl-cobamide containing protein from Sporomusa ovata have been obtained from polyethyleneglycol solutions at pH 8.5 by the hanging drop technique. The crystals belong to space group C222(1) with cell dimensions a = 110.5(0.2) A, b = 144.0 (0.2) A, c = 110.4 (0.1) A. They diffract to 2.2 A resolution on a rotating anode X-ray source and are suitable for high resolution X-ray diffraction studies.