1D- and 2D-INADEQUATE NMR data for two poly(styrene-alpha-C-13) samples are presented. They represent the first recorded detection of the head-to-head enchainments in polystyrene that result when polystyrene radicals terminate by combination. Resonances that are attributable to structures resulting from head-to-head propagation reactions and to a terminal methylene carbon, which may have been produced either by a chain transfer reaction or by a disproportionation termination reaction, have also been detected. The C-13 NMR spectra of several polymers and copolymers that serve as models for head-to-head enchainments in polystyrene are also discussed.