The purposes of this study were to(a) develop theoretical modifications of the extended gate control theory of pain using Fishbein's model and(b) test the efficacy of these modifications. Attitude, social subjective norm, personal subjective norm, habit and state anxiety were operat-ionalized to represent internal stimuli for the cognitive-evaluative and motivational-affective dimensions of the theory. Pain expression was operationalized as sensory and affective responses to pain, and pain endurance. Sixty-two female nurses from 20 to 50 years of age participated. A semantic differential scale measured attitude and motivations to comply; a Likerty-type scale measured personal and social norms and habit. Spielberger's STAI measured state anxiety. Pain was produced using a modified submaximum effort tourniquet technique. Pain expression was measured using ratio scales of sensory intensity and unpleasantness developed by Gracely and his associates. Pain endurance was measured by subtracting time of pain threshold from pain tolerance. The first hypothesis examining whether pain endurance would be more significantly related to the affective response than to the sensory response was not rejected. Four remaining hypotheses, testing the ability of the five variables to predict the sensory and affective responses were not rejected. However, the habit of pain expression and the attitude toward pain expression contributed to the prediction of both sensory and affective responses to pain. The interaction between the cognitive-evaluative and the sensory-discriminative dimensions and the interaction between the cognitive-evaluative and motivational-affective dimensions were partially supported by the data from these two variables. The interaction between the motivational-affective and the sensory-discriminative dimensions was also supported by the relationship of sensory "to affective responses. The variables which did not significantly predict pain expression appeared to have potential for prediction. Revision and testing of the tools for better reliability, validity, and clinical usuability are needed. The study contributed to theory building. The identification of variables which predict pain behavior must occur before effective nursing interventicuis can be developed.