Reported here are measurements of the rotational spectra of two isotopologues (Cl-35 and Cl-37) of one of the simplest chiral carboxylic acids, 2-chloropropionic acid. The spectra have been obtained in a supersonic expansion, using free-jet millimeter-wave direct-absorption as well as pulsed-jet FT microwave spectroscopies. A single conformer has been detected, characterized by a methyl group nearly cis with respect to the carbonylic oxygen. Within the realm of chiral recognition, the relative simplicity of the observed spectrum should allow for the detection of the microwave spectrum of the polar homo-dimer. (C) 2008 Elsevier B. V. All rights reserved.