Haemoglobin acts as an important protein for oxygen carrier in all living beings. Purification of donkey haemoglobin was done using PEG 4000 as a separating medium. Crystallization was achieved using hanging drop vapor diffusion method using 2.8 M phosphate buffer, pH 6.8. Data collection was done using mar345 image plate detector system. The crystals grown under 2.8 M phosphate buffer are monoclinic with space group C2 and cell dimensions a = 107.664 Angstrom, b = 63.084 Angstrom, c = 54.042 Angstrom, and beta = 111.747degrees. (C) 2003 Elsevier Inc. All rights reserved.