A new procedure for the synthesis of the unstable beta-polymorph of glycine has been developed. The amount of the sample synthesized in one run is enough to carry out the calorimetric measurements. The transformation of beta-glycine into alpha-glycine on heating was investigated. The transformation starts at 340 K as an exothermic process and takes some time for the completion. This agrees with the recent results of X-ray single crystal investigations showing that the beta-alpha transformation is the recrystallization. (C) 2002 Published by Elsevier Science B.V.