The ORF XF2234 in the Xylella fastidiosa genome was identified as encoding a small heat-shock protein of 17.9 kDa (HSP17.9). HSP17.9 was found as one of the proteins that are induced during X. fastidiosa proliferation and infection in citrus culture. Recombinant HSP17.9 was crystallized and surface atomic force microscopy experiments were conducted with the aim of better characterizing the HSP17.9 crystals. X-ray diffraction data were collected at 2.7 angstrom resolution. The crystal belonged to space group P4(3)22, with unit-cell parameters a = 68.90, b = 68.90, c = 72.51 angstrom, and is the first small heat-shock protein to crystallize in this space group.