Abstract Depression increases cardiovascular risk and involves worse clinical outcomes. Little attention is paid to it in hospitalized patients. We studied prevalence and determinants of depression in this group, in order to select patients for further specific management. Methods Consecutive patients admitted to Cardiology wards were included. Cardiovascular risk factors, clinical and psychosocial data were collected. Self perceived mental and physical health quality were assesed by 12-item Short Form survey (SF-12), and Hospital Anxiety and Depression Scale (HADS) questionnaires were administered. Statistical analysis was performed using Spearman´s correlation, Mann-Whitney and Fisher tests, and Mantel-Cox, linear and logistic regression analyses. Results 170 consecutive patients, median age 74.5 (67.2-81.1), 59.4% male, were included. Most common pathologies were heart failure (44.7%) and coronary syndroms (28.8%). According to HADS results, depression was probable (score >10) in 10%, and at least possible (score > 8) in 27.1%. Both increased duration of hospitalization (Median 14 vs 7 days;p=0.016 and 11 vs 7 days;p=0.005 respectively). Anxiety was present in 16.5 % for probable case and 34.1% for possible case, with no significant change in median duration of hospitalization. 22.9% of patients were under antidepressant treatment, and 24% under anxiolytics, but they were added to treatment only in 1% and 7% respectively. No other not pharmacological measure was initiated. Self perceived mental health was diminished in probable depression (mean difference 14.9%;95%IC 9.7-20.2;p<0.001). Self perceived physical health was also lower (mean difference 6.4%;95%CI:1.1-11.8;p=0.016). Patients with depression were a mean of 5.6 years older (95%CI 1.4-9.8;p=0.032). Less than primary education (OR 5.69 (p 0.021), and Previous hospital admission OR 3.2 (1.0-10.3;p=0.034) increased the risk of depression in univariate analysis. By multivariate analysis, determinants of depression were anxiety (OR 22.5;95%CI 5.9-85.6;p<0.0001), need for surgery (OR 12.3;95%IC 2.1-73.2;p=0.009), need for intensive care unit surveillance (OR 4.2;95%CI 1.1-15.8;p=0.039), and age (OR 1.1;95%IC 1.0-1.2;p=0.001. AUC was 0.89;95%CI 0.81-0.96;p<0.0001. There was no difference in civil status, gender, income level, living accompanied, number of comorbidities, cardiovascular risk factor or reason for hospital admission. Conclusions Depression was prevalent in our hospitalized cardiac patients,in spite of previous pharmacological treatment. It prolongs duration of stay and impacts negatively in self perceived mental and physical health. Risk is increased in older people requiring intensive care surveillance or surgery, and specially by anxiety. These patients could benefit from a preventive multifactorial approach. Attention should also be paid to patients with a previous hospitalization and low educational level.ROC curve for multivariate model