Purpose <p>This study was conducted to evaluate the level of hope and adherence to medication in women with breast cancer in the presence of another chronic disease.</p> Methods <p>The cross-sectional study was conducted in March-August 2022 with women with breast cancer with (CVD group) and without (Non-CVD group) cardiovascular disease as a chronic disease. Data were collected with the 'Individual Information Form', 'Herth Hope Scale' and 'Medication Adherence and Prescription Writing Scale'. Independent Sample T-test, Mann Whitney U Test, Chi-Square Test and Correlation Analysis were used to analyze the data.</p> Results <p>Adherence to medication levels of the patients were higher with a mean score of 8.55 ± 2.16 in the CVD group and 8.33 ± 2.14 in the Non-CVD group and there was no difference between the two groups (p &lt; 0.05). When the hope levels of the patients were evaluated; the hope level of the CVD group was 69.57 ± 9.58 and the hope level of the Non-CVD group was 74.96 ± 7.98. The hope level of the CVD group was lower than that of the Non-CVD group (p &lt; 0.001, Cohen’s <i>d</i> = 0.61).</p> Conclusion <p>In women, the presence of a chronic (cardiovascular) disease in addition to breast cancer does not affect medication adherence but negatively affects the level of hope.</p>