The reactions of cycloalkanes with CO via the C-H bond activation by Pd(OAc)2 catalyst have been found to proceed regio- and stereo-selectively to give corresponding carboxylic acids. The reactivity of C-H bonds of cyclo-alkanes decreases in the order: tert- > sec- > prim-carbon, and the stereochemistry of the substituents on the main products is all equatorial.