In order to analyze the alanyl-tRNA synthetase from the archaeon Archaeoglobus fulgidus, the N-terminal fragment lacking the dimerization domain and the C-terminal dimerization-domain fragment were each overexpressed in Escherichia coli, purified and crystallized. A 3.7 A resolution data set was collected for the N-terminal fragment. The crystal belongs to the tetragonal space group P4(1) or P4(3), with unit-cell parameters a = b = 101.15, c = 124.24 A. For the C-terminal fragment, a SeMet MAD data set was collected to 3.2 A resolution. The crystal belongs to the orthorhombic space group P222(1), with unit-cell parameters a = 124.15, b = 131.91, c = 138.68 A.