Understanding the mood state and its relationship with quality of life (QOL) of mastectomy recipients can serve as baseline within which a sound rehabilitation program can be developed. This study therefore was conducted to facilitate a better understanding of participants' postmastectomy mood states, identify their potential predictors, identify clusters of mood profiles, and clarify between-cluster differences in terms of QOL. Hong Kong mastectomy patients completed the Profile of Mood States and Ferrans and Powers Quality of Life Index. We extended the complementary strengths of the application of both variable- and person-centered approaches to clarify relationships and to identify profiles of mood states in relation to QOL in a sample of 200 women who had undergone a mastectomy in Hong Kong. Simultaneous regression identified age and educational attainment as predictors of mood states, and cluster analysis identified three distinct mood profiles that are able to explain differences in various measures of QOL after mastectomy. Implications for future research and practice are discussed.