The purpose of this study was to determine the intra- and inter-rater reliability of selected variables measuring motor function in adults following severe traumatic brain injury (TBI). Twelve adults with a severe TBI participated in the study and were assessed (independently) by two physical therapists with extensive clinical experience. Standardized testing protocols and two- or three-point ordinal rating scales were used to evaluate the following categories of variables: primitive reflexes, equilibrium/protective reactions and several motor skills. Intra-rater reliability was generally high for all variables, with kappa values exceeding 0.65 except for the scoring of equilibrium reactions in sitting and standing. Overall, inter-rater reliability was slightly lower, with kappa values ranging from 0.39 to 1.0, indicating 'fair' to 'almost perfect' agreement. The highest level of agreement was consistently reported for the scoring of motor skills. These results suggest that physical therapists trained in the use of standardized testing and scoring procedures can reliably assess primitive reflexes, equilibrium and protective reactions and a range of motor skills in TBI adults during the acute stage of recovery. Moreover, the results provide important information which will assist in the interpretation of data collected as part of a concurrently conducted longitudinal study of early motor recovery.