Methionyl-tRNA(fMet) formyltransferase from Escherichia coli, a monomer of 34kDa, was overexpressed from its cloned gene fmt (Guillon, J.M., Mechulam, Y., Schmitter, J.M., Blanquet, S., and Fayat, G., J. Bacteriol. 174:4294-4301, 1992) and crystallized using ammonium sulphate as precipitant. The crystals are trigonal and have unit cell parameters a = b = 151.0 A, c = 81.8 A. They belong to space group P3(2)21 and diffract to 2.0 A resolution. The structure is being solved by multiple isomorphous replacement.