The X-ray structures of new iodine-containing derivatives of trifluoroacetamide: N-(1-cyclohexyl-2-iodoethyl)trifluoroacetamide (1), N-(2-iodo-1-phenylethyl)trifluoroacetamide (2), and N-(5-iodocyclopent-2-en-1-yl)trifluoroacetamide (3) have been determined. The conformers of amides 1, 2 and their structural analogue N-[2-iodo-1-(p-chlorophenyl)ethyl]trifluoroacetamide (4) with respect to rotation about the CCH2I bond were studied by FT-IR spectroscopy [along with N-(5-iodocyclopent-2-en-1-yl)trifluoroacetamide (3) and N-(6-iodocyclohex-2-en-1-yl)trifluoroacetamide (5)] and analyzed by quantum chemical calculations (B3LYP/DGDZVP).