The crystal structure of the title compound, C6H6N2O2·H2O, consists of N-hydroxypicolinamide and water molecules connected through O—H...O and N—H...N hydrogen bonds. The O—H...O interactions and π–π stacking interactions between the pyridine rings [centroid–centroid distance = 3.427 (1) Å] organize the components into columns extending along the b axis and the N—H...N hydrogen bonds link these columns into a two-dimensional framework parallel to (100). The N-hydroxypicolinamide molecule adopts a strongly flattened conformation and only the O—H group H atom deviates significantly from the molecule best plane. The dihedral angle between the hydroxamic group and the pyridine ring is 5.6 (2)°. The conformation about the hydroxamic group C—N bond is Z and that about the C—C bond between the pyridine and hydroxamic groups is E.