[show abstract][hide abstract] ABSTRACT: Objective: The experiences of positive adjustment and growth, termed Posttraumatic Growth (PTG), are commonly reported among cancer survivors in the years after treatment. However, few studies have examined PTG among patients in active treatment for cancer. This study examined both positive and negative valenced change in PTG and relationships with treatment-related symptoms and mental and physical quality of life (QOL) among adults in active cancer treatment. Methods: In this cross-sectional study, adult outpatients (n = 114) completed a self-administered questionnaire. Hierarchical linear regression modeling (HLM) was performed to examine unique associations between positive and negative valenced change in PTG and QOL subscales and symptom reporting, controlling for theoretically relevant sociodemographic variables. Results: The majority of participants (87%) reported at least one positive life change, whereas half (50%) reported at least one negative life change across PTG items. In HLM analysis of QOL subscales, negative valence PTG scores were positively associated with Physical Functioning and Bodily Pain and inversely associated with General Health, Role Physical, and Mental Health (F(12, 71) = 5.13; p < .0001). In HLM analysis of treatment symptom burden, positive valence PTG scores were inversely associated with age at diagnosis and reports of nausea (F(8, 83) = 2.93; p = .007). Conclusions: Reports of positive and negative life changes since diagnosis are common among adults actively receiving treatment for cancer. Assessments of both valenced PTG scores can provide a broader profile of biopsychosocial adjustment and symptom reporting during cancer treatment. (PsycINFO Database Record (c) 2012 APA, all rights reserved).