The molecular dynamics of ethyl radical decomposition has been studied by Monte Carlo classical trajectories. Hydrogen atom migration between the carbon atoms is found to be a minor path in comparison to C2H 5→H + C2H4 dissociation. Strong coupling exists between the H-atom and the C2H4 moiety during the dissociation process. This coupling significantly broadens the resultant distributions in product impact parameter, orbital angular momentum, and relative translational energy and shifts them to higher values than predicted by RRKM on minimum energy path arguements. The dissociation dynamics of C 2H4D→D + C2H4 are nearly identical to those for C2H5→H + C2H 4. At 100 kcal/mole excitation, ethyl radical dissociation is predicted to be an intrinsically non-RRKM process. There does not appear to be a dividing surface that separates the reactant and product regions of the C 2H5⇄H + C2H4 phase space.