Depression is commonly reported in coronary artery bypass graft (CABG) surgery patients. This study assesses the relationship of preoperative characteristics, life stressors, social support, major cardiac and neurologic outcomes and other complications to depressive symptomatology. Demographic and clinical data, CES-D score and information on life stressors and social support were collected from 237 patients; 92% completed 6-month follow-up. CES-D score > or = 16 was defined as significant depressive symptomatology. Significant depressive symptomatology was found in 43% of patients preoperatively and 23% postoperatively. In multivariate models, low social support (p = 0.008), presence of at least one life stressor within a year of surgery (p = 0.006), moderate to severe dyspnea (p = 0.003), little to no available help (p = 0.05) and less education (p = 0.05) were associated with higher preoperative CES-D score, while longer intensive care unit (ICU) stay (p = 0.0001) and little or no available help (p = 0.0008) predicted higher postoperative CES-D scores when controlling for preoperative CES-D scores. Neither pre- nor postoperative depressive symptomatology was related to major outcomes or other complications. A high rate of significant depressive symptomatology exists in CABG patients preoperatively, and it decreases significantly postoperatively. Patients with the above preoperative characteristics as well as those who stay in the ICU postoperatively for more than 2 days might benefit from psychosocial interventions.