Human cytosolic seryl-tRNA synthetase (hsSerRS) is responsible for the covalent attachment of serine to its cognate tRNA(Ser). Significant differences between the amino-acid sequences of eukaryotic, prokaryotic and archaebacterial SerRSs indicate that the domain composition of hsSerRS differs from that of its eubacterial and archaebacterial analogues. As a consequence of an N-terminal insertion and a C-terminal extra-sequence, the binding mode of tRNA(Ser) to hsSerRS is expected to differ from that in prokaryotes. Recombinant hsSerRS protein was purified to homogeneity and crystallized. Diffraction data were collected to 3.13 Å resolution. The structure of hsSerRS has been solved by the molecular-replacement method.