Pressure-dependent internal rotation rate constants for [N-15]formamide in gas mixtures containing 1.3 Ton of [N-15]formamide and SF6 pressures ranging from 150 to 5225 Ton were determined from analysis of exchange-broadened H-1 NMR spectra obtained at 333 K. They agree well with RRKM calculations using experimental vibrational frequencies and rotational constants for the ground state and appropriately scaled 6-311++G** parameters for the transition states. The strong collision model, with a hard sphere diameter of 4.8 Angstrom, yields satisfactory agreement. Activated formamide molecules have an average calculated energy specific rate constant, [k(E)], of ca. 5.3 x 10(9) s(-1) and a state density of ca. 7.2 cm(-1). Statistical internal rotation kinetics requires activated formamide molecules to have vibrational lifetimes of <200 ps and average intervibrational coupling matrix elements of greater than or equal to 0.1 cm(-1). These results are compared to kinetic studies of similar low-energy unimolecular processes.