NAD kinase from Mycobacterium tuberculosis (Ppnk) uses ATP or inorganic polyphosphate [poly(P)]. Ppnk overexpressed in Escherichia coli was purified and crystallized in the presence of NAD. Preliminary X-ray analysis of the resultant crystal indicate that the crystal belongs to hexagonal space group P6(2)22 and is holo-Ppnk complexed with NAD.