Cancer-related fatigue (CRF) is a common and distressing side-effect of cancer treatment. The present study developed a brief version of the Illness Perception Questionnaire (IPQ) for assessing patients' representations of CRF. Cancer patients and survivors (n = 155) completed a revised version of the IPQ as well as measures of fatigue severity at two different time-points. Confirmatory factor analysis at both Time 1 and 2 showed that the seven-factor solution based on the Self-Regulation Model fit the data adequately and factorial invariance over the two time-points was supported. The resulting subscales exhibited good internal consistency and test-retest reliability. The adapted version of the IPQ shows promise for the assessment of patient perceptions regarding CRF. The scale may be able to be used clinically to identify if patients have inaccurate or unhelpful representations of CRF and to help tailor interventions for persistent fatigue in cancer survivors.