The concepts of pain and discomfort are poorly differentiated in the literature. This study of 417 post-operative orthopaedic patients examined their use of language to describe pain and also discomfort. Their pain descriptions were assessed for congruence with the widely used McGill pain questionnaire (MPQ). The findings confirmed that there was an overlap in the descriptions of pain and discomfort, but that pain tended to be described as an internal phenomenon, while discomfort was frequently related to environmental stimuli. The use of analogy was commonly used to describe pain. There was considerable use of words not included in the MPQ. This suggests that regional and international variations in vocabulary may render the MPQ unsuitable for indiscriminate use in Anglophone countries. Implications for improving pre-operative information provision and post-operative assessment of pain and discomfort are briefly presented.