A new novel amino acid ionic liquid [C(4)mim][Gly] (1-butyl-3-methylimidazolium glicine) was prepared by the neutralization method. The molar enthalpies of solution, Delta H-sol(m)(wc), of [C(4)mim][Gly] with various amounts of water and with various molalities were measured by the solution-reaction isoperibol calorimeter at (298.15 +/- 0.01) K. According to Archer's method, the standard molar enthalpies of solution of [C(4)mim][Gly] with known amounts of water, Delta H-sol(m)0(wc), were obtained. To eliminate the effect of the small amount of water in [C(4)mim][Gly], a linear fitting of Delta H-sol(m)0(wc) against water content was carried out so that a good straight line was obtained, and the intercept was the standard molar enthalpy of solution of [C(4)mim][Gly] without water, Delta H-sol(m)0= (-46.02 +/- 0.19) kJ center dot mol(-1). Using Glasser's lattice energy theory, the hydration enthalpy of the glycine anion [Gly](-) was estimated.