Objective: Appearance investment can be considered an important factor in the explanation of individual differences in adjustment to breast cancer. This study aims to analyze the role of this variable on a set of adjustment outcomes, namely, quality of life (QOL), emotional adjustment (depression and anxiety) and fear of negative evaluations. The differential role of motivational salience facet of appearance investment (MS; the individual's efforts to be or feel attractive), conceptualized as a protective factor, and of self-evaluative salience facet (SES; the importance an individual places on physical appearance for their definition of self-worth), conceptualized as a vulnerability factor, is explored. Methods: This cross-sectional study included 117 Portuguese breast cancer patients (mean age = 52.47; SD = 8.81), on average 2.32 months (SD = 2.17) post-diagnosis. Appearance investment was measured by the ASI-R; QOL by the WHOQOL-bref; emotional adjustment by the HADS; and fear of negative evaluations by the FNE (Portuguese versions). Several hierarchical multiple regressions were conducted for each outcome, using investment facets as a predictor variable. Results: Both facets of investment contributed to the explanation of social (p <= 0.001) and psychological (p <= 0.001) QOL and also depression (p <= 0.001), with SES being associated with poorer results and MS with better outcomes. SES also predicted higher levels of fear of negative evaluations (p <= 0.001). Conclusions: This study provided significant information about the role of appearance investment in the adjustment of breast cancer patients and added empirical support to SES-MS distinction. Copyright (C) 2009 John Wiley & Sons, Ltd.