Crystals of the Saccharomyces cerevisiae elongation factor eEF1A (formerly EF-1 alpha) in complex with a catalytic C-terminal fragment of the nucleotide-exchange factor eEF1B alpha (formerly EF-1 beta) were grown by the sitting-drop vapour-diffusion technique, using polyethylene glycol 2000 monomethyl ether as precipitant. Crystals diffract to better than 1.7 A and belong to the space group P2(1)2(1)2(1). The unit-cell parameters of the crystals are sensitive to the choice of cryoprotectant. The structure of the 61 kDa complex was determined with the multiple anomalous dispersion technique using three selenomethionine residues in a 11 kDa eEF1B alpha fragment generated by limited proteolysis of full-length eEF1B alpha expressed in Escherichia coli.