Background: Limited data exists regarding how pre-diagnosis self-reported health-related quality of life (HRQOL) and mood disorders may impact treatment decisions for DCIS. Methods: We used the population-based SEER-MHOS linked dataset to assess impact of pre-diagnosis patient-reported HRQOL and major depressive disorder (MDD) on treatment decisions of older women with DCIS. Participants were women age ≥ 65 years who completed the MHOS ≤ 6 months before DCIS diagnosis. Predictor variables were MDD risk, Physical Component Summary (PCS), and Mental Component Summary (MCS) scores (measured by Short Form-36/Veterans RAND 12-item surveys). Presence of MDD risk was determined using a published algorithm based on response to four MHOS items. Associations between predictors and receipt of radiation therapy after breast conserving surgery (BCS+RT) versus surgery alone (BCS or mastectomy [MTX]) were assessed with univariate and multivariable logistic regression (MVA). Pre-specified covariates for MVA were age, number of comorbidities, diagnosis year, and marital status. Results: We identified 135 older women diagnosed with DCIS between 1998-2011 treated with BCS+RT (41%, n = 55), BCS (30%, n = 40), or MTX (30%, n = 40). Of these, 24% (n = 32) were at risk for MDD within 6 months before diagnosis. Among those at risk for MDD, 25% (n = 8) received BCS+RT, 34% (n = 11) BCS, and 41% (n = 13) MTX. Those at risk for MDD were less likely to receive BCT+RT relative to surgery alone (BCS/MTX; odds ratio [OR] 0.40, 95 % confidence interval [95% CI] 0.16 – 0.97, p = 0.04). After pre-specified covariate adjustment, women at risk for MDD remained less likely to receive BCS+RT (OR 0.30, 95% CI 0.12 – 0.80, p = 0.02). Backward selection MVA identified MDD risk and age as significant independent predictors for treatment. There were no significant associations between pre-diagnosis MCS or PCS and treatment. Conclusions: Older women at risk for MDD prior to DCIS diagnosis were less likely to receive RT after BCS compared to surgery alone. To our knowledge, this is the first study examining associations between DCIS treatment decisions and patient-reported HRQOL and MDD data collected prior to diagnosis.