Intramolecular Michael cyclization led directly to 2-amino-2-thiazoline-4-ethanoic acid, a new and potent member of the limited group of specific GABA, receptor agonists. 2-Amino-2-thiazoline-4-ethanoic acid is unknown, although the corresponding aromatic thiazole features in the 7S-acylamino side chain of certain B-lactam antibiotics. We now describe a brief entry to the title compound, and its biological activity as a GABA mimetic.