C14H18N2O4.H2O, Mr = 296.32, triclinic, P1, a = 5.524 (3), b = 6.621 (2), c = 10.307 (2) A, alpha = 78.82 (3), beta = 86.82 (4), gamma = 84.96 (4) degrees, V = 368.11 A3, Z = 1, Dx = 1.34 g cm-3, lambda(Mo K alpha 1) = 0.70930 A, mu = 1.10 cm-1, F(000) = 158, T = 298 K, final R = 0.044 for 2182 observed reflections. The molecule crystallizes as a zwitterion with the peptide backbone folded and a water molecule of hydration. The water molecule and the dipeptide molecule are involved in an extensive hydrogen-bond network.