The Ar-, Kr-, and Xe-insertion compounds into acrylic acid, i.e., C(2)H(3)COONgH (Ng = Ar, Kr, and Xe), have been studied by ab initio calculations. The geometry optimization, frequency calculation, and stability were investigated at the MP2/aug-cc-pVTZ (aug-cc-pVTZ-PP) level of theory. Two configuration isomers, i.e., s-cis syn (isomer A) and s-cis anti (isomer B), were optimized for each molecule. Using the s-cis syn structure (isomer A) as an example, we performed natural bond orbital (NBO) analysis, natural energy decomposition analysis (NEDA), and atom-in-molecules (AIM) analysis to investigate the bonding nature of these noble-gas compounds. Our study predicts the existence of Kr- and Xe-derivatives of acrylic acid and the instability of Ar-related compounds.