The aim of this study was to compare the accuracy of performance predictions in experimental tasks with patients' awareness of activity limitations. Participants were 24 patients with brain injuries (i.e., traumatic brain injury and cerebrovascular disorders) and 22 patients with orthopedic disorders. Prediction of performance was examined in a memory task (word list learning) and a motor task (finger tapping). Awareness of activity limitations was measured by comparing patients' self-ratings and staff ratings in the Patient Competency Rating Scale (PCRS). Results for the PCRS showed that patients with orthopedic disorders underestimated and patients with brain injuries (i.e., patients with TBI) overestimated their level of functioning in the total scale and the social/emotional subscale in comparison to staff ratings. Both patient groups agreed with staff ratings in physical/basic self-care items. In the predicted performance tasks a similar pattern could be observed: None of the groups showed an overestimation of performance in the motor task, whereas patients with brain injuries overestimated their competency in the memory task. However, the agreement between both awareness measures (PCRS, predicted performance) was only low, which indicates that they might measure different aspects or levels of self-awareness.