Cognitive and affective psychosocial factors have been found to underlie adherence to preventive behaviors in women at risk of developing lymphedema following treatment for breast cancer. The aim of this study was to determine if these factors are associated with adherence to self-management behaviors for women diagnosed with breast cancer-related lymphedema (BCRL). Women with BCRL were recruited through a community-based breast cancer organization and three Australian lymphedema treatment clinics. Participants completed an online questionnaire assessing demographics, medical history, adherence to self-management behaviors, psychosocial variables (personal control, treatment control, consequences, distress, and self-regulation of affect), and knowledge about lymphedema self-management. A total of 166 women participated in the study. Participants reported adhering to a mean of five out of seven behaviors, with 19.5 % of participants adhering to all seven behaviors. Adherence to individual behaviors ranged from 65 % (self-lymphatic drainage) to 98.2 % (skin care). Greater knowledge about lymphedema was significantly correlated with higher adherence. Hierarchical multiple linear regression analysis indicated that only medical history factors (time since diagnosis and having undergone hormone replacement therapy) predicted a significant amount of the variance in adherence. These findings highlight the importance of patient knowledge for optimal adherence to a self-management regimen. In addition, medical history factors may identify if a patient is at risk of nonadherence. The lack of association of adherence with other psychosocial factors considered in this study indicates that factors underlying adherence in affected women differ considerably from those factors prompting preventive behavior adherence in the at-risk population.