In the title compound, C(5)H(5)N(3)O, the isoxazole ring is essentially planar, with a maximum deviation of 0.007 (1) Å from the least-squares plane. The N atom of the amine group exhibits sp(2) character (sum of bond angles around this atom = 358°). In the crystal, mol-ecules are aggregated by two kinds of N-H⋯N hydrogen bonds into fused R(2) (2)(12) and R(6) (6)(26) rings, forming a slightly puckered two-dimensional array lying parallel to (101).