OBJECTIVE: To determine the prevalence of anxiety and depression in patients complaining of chest pain who seek a chest pain unit attendance. INTRODUCTION: Patients arriving at a Chest Pain Unit may present psychiatric disorders not identified, isolated or co-morbid to the main illness, which may interfere in the patient prognosis. METHODOLOGY: Patients were assessed by the "Hospital Anxiety and Depression Scale" as a screening instrument wile following a systematized protocol to rule out the diagnosis of acute coronary syndrome and other potentially fatal diseases. Patients with 8 or more points in the scale were considered "probable case" of anxiety or depression. RESULTS: According to the protocol, 59 (45.4%) of 130 patients studied presented Chest Pain of Determined Cause, and 71 (54.6%) presented Chest Pain of Indefinite Cause. In the former group, in which 43 (33.1%) had acute coronary syndrome, 33.9% were probable anxiety cases and 30.5% depression cases. In the second group, formed by patients without acute coronary syndrome or any clinical conditions involving greater morbidity and mortality risk, 53.5% were probable anxiety cases and 25.4% depression. CONCLUSION: The high anxiety and depression prevalence observed may indicate the need for early and specialized approach to these disorders. When coronary arterial disease is present, this may decrease complications and shorten hospital stay. When psychiatric disorder appears isolated, is possible to reduce unnecessary repeated visits to emergency room and increase patient's quality of life