The microwave spectrum of 2-chloroacetamide (ClCH2CONH2) has been investigated at room temperature in the 19-80 spectral range. Spectra of the (ClCH2CONH2)-Cl-35 and (ClCH2CONH2)-Cl-37 isotopomers of one conformer, which has a symmetry plane (C, symmetry), were assigned. The amide group is planar, and an intramolecular hydrogen bond is formed between the chlorine atom and the nearest hydrogen atom of the amide group. The ground vibrational state, six vibrationally excited states of the torsional vibration about the CC bond, as well as the first excited state of the lowest bending mode were assumed for the (ClCH2CONH2)-Cl-35 isotopomer, whereas the ground vibrational state of (ClCH2CONH2)-Cl-37 was assigned. The CC torsional fundamental vibration has a frequency of 62(10) cm(-1), and the bending vibration has a frequency of 204(30) cm(-1). The rotational constants of the ground and of the six excited states of the CC torsion were fitted to the potential function V(z) = 16.1(< z(4)> + 2.3 < z(2)>) cm(-1), where z is a dimensionless parameter. This function indicates that the equilibrium conformation has C, symmetry. Rough values of the chlorine nuclear quadrupole coupling constants were derived as chi(aa) = -47.62(52) and chi(bb) = 8.22(66) MHz for the Cl-35 nucleus and chi(aa) = -34.6(10) and chi(bb) = 6.2(11) MHz for the Cl-37 nucleus. Ab initio and density functional theory quantum chemical calculations have been performed at several levels of theory to evaluate the equilibrium geometry of this compound. The density functional theory calculations at the B3LYP/6-311++G(3df,2pd) and B3LYP/cc-pVTZ levels of theory as well as A initio calculations at the MP2(F)/cc-pVTZ level predict correct lowest-energy conformation for the molecule, whereas the ab initio calculations at the QCISD(FC)/6-311G(d) and MP2(F)/6-311++G(d,p) levels predict an incorrect equilibrium conformation.