The McGill Pain Questionnaire (MPQ) aims to measure sensory, affective, and evaluative dimensions of pain. However, the structural dimensionality of the MPQ remains somewhat uncertain. Exploratory (EFA) factor analyses were used to investigate the structure of the MPQ based on the responses of a diverse sample of 448 pain patients (M age = 43.1 yr., SD = 19.3). The EFA employed a methodologically sound iterative maximum-likelihood procedure, together with direct oblimin oblique simple structure rotation. Perusal of the 3-, 4-, and 5-factor solutions suggested that the MPQ measures two separate sensory dimensions of pain, while aff ective and evaluative dimensions were not sharply delineated, suggesting that the MPQ structure requires some revision.