Background: Breast cancer (BCa) is the most common cancer in women. Adjuvant hormone therapy (AHT) showed consistent improvements in recurrence and survival rates. AHT use is associated with multiple side effects that cause a lack of adherence. This report aims to describe the symptom burden of BCA patients at treatment initiation from our ongoing RCT, which is directed at improving adherence through the innovative use of smart pill bottles. Methods: Descriptive statistics included socio-demographic information and medication use. Symptom burden and distress are assessed using the breast cancer prevention trial (BCPT) symptom scales. Self-efficacy is assessed using a modified version of Lorig’s Chronic Disease Self-Efficacy Scale for managing symptoms. Results are summarized as means (M), standard deviation (SD), ranges (R), and percentages. The relationship between patients’ symptoms and self-efficacy was analyzed using a multivariable linear regression model controlling for age and race. Results: Of the 119 patients included, the majority were White 80.7 %, with ages ranging from 31-81 with a mean age of 59.74 (SD=11.057). The majority had a college education or higher (61.3 %), married (66.4%), full-time workers (42.9 %) and had incomes of 75,000 USD or higher (59.0 %). The patients were on either Tamoxifen (17.7%), Anastrozole (55.4%), Letrozole (12.3%) or Exemestane (4.6 %). The (BCPT) subscales were; vasomotor symptoms (R=0-12.5, M= 5.8, SD= 3.14), Gastrointestinal symptoms (R=0-7.5, M= 2.97, SD= 1.14), bladder control (R=0-10, M= 3.09, SD= 1.87), Dyspareunia subscale (R=0-10, M= 3.53, SD= 2.27), Musculoskeletal pain (R=0-15, M= 7.5, SD= 3.53), Weight concerns (R=0-10, M= 4.22, SD= 2.16), Cognitive symptoms (R=0-15, M= 6.02, SD= 2.81). For the LORIG scales (R=1- 8.83, M= 6.04, SD=1.61). Patient symptoms were inversely correlated with higher LORIG scores for vasomotor symptoms (β = -.18, t(3) = -2.00, p= .048), Gastrointestinal symptoms (β = -.27, t(3) = -2.92, p= 0.004), Musculoskeletal pain (β = -.378, t(3) = -4.31, p= .000), Weight concerns (β = -.286, t(3) = -3.26, p= .0002), Cognitive symptoms (β = -.34, t(3) = -3.841, p= .000). Conclusions: Our results explore symptom burden and distress for breast cancer patients on AET. Based on the BCPT instrument subscales, musculoskeletal symptoms tend to be the most intrusive, with the highest mean score. Symptom burden was inversely related to higher self-efficacy represented by LORIG scores. This needs to be validated with further analysis in comparison to a control group across time points in the study to determine what would be a minimally important difference or change in score. This will help understand the interrelationships between physical symptoms and adherence to AHT. Clinical trial information: NCT04086875.