People with cancer often report that they experience personal growth as a result of the disease, but such reports have unclear validity. Some suggest such growth results from Rogers's (1951) hypothesized organismic valuing process (OVP), an innate tendency for people to gravitate toward well-being; others suggest this growth may be a positive illusion resulting from temporal self-comparisons. To test these conceptualizations, the authors examined 83 individuals with Stages 0-III breast or prostate cancer. Patients completed measures of positive attributes and personal life goals before radiotherapy (Time 1) and after radiotherapy (Time 2). At Time 2, participants also attempted to recreate their Time 1 responses and completed a posttraumatic growth (PTG) measure. PTG was significantly related with actual increases (but not perceived increases) in the relative importance of intrinsic goals versus extrinsic goals and with perceived increases (but not actual increases) in positive attributes. These measures were unrelated to one another and thus explained unique variance in PTG. Data suggest that both actual change processes related to the OVP and biases in autobiographic recall may independently contribute to PTG reports.