A single coronary artery is a rare anomaly that may be associated with myocardial ischemia and sudden death. We present a case of a young woman with atypical angina whose coronary angiography revealed a right coronary artery originating from the mid left anterior descending artery, a variant of the single coronary artery. DESCRIPTORS: RESUMO Artéria Coronária Direita Originada da Artéria Descendente Anterior: Uma Rara Anomalia CoronarianaA artéria coronária única é anomalia rara, que pode estar associada à isquemia miocárdica e morte súbita. Apresentamos o caso de uma mulher jovem, com quadro de angina atípica, cujo cateterismo revelou artéria coronária direita que se originava do terço médio da artéria descendente anterior, uma variante da artéria coronária única. DESCRITORES:Anomalias dos vasos coronários. Angiografia coronária. Anomalias dos vasos coronários/diagnóstico. Diagnóstico por imagem/métodos. Case Report Congenital coronary artery anomalies are found in 0.3 to 5.6% of patients undergoing coronary angiography and in 0.3% of autopsies.1 The presence of a single coronary artery, characterized as a coronary artery with its origin in one of the sinuses of Valsalva and that irrigates the entire heart, is a rare anomaly, representing 3.31% of all coronary congenital anomalies, and can be associated with myocardial ischemia and sudden death. This report details the case of a female patient whose right coronary artery had its origin from the left anterior descending artery, a variant of single coronary artery (type LII of Lipton's classification). 2 CASE REPORTFemale patient, 42 years old, with a history of a stabbing retrosternal chest pain, not related to physical effort, which had begun 2 months previously. The patient had a history of hypertension, dyslipidemia, and obesity, and a family history of premature coronary disease. Physical examination and electrocardiogram (ECG) at rest were normal. The stress test was positive for ischemia by electrocardiographic criteria (ST-segment depression of 1 mm in the inferior leads and in MC5), with indication for coronary angiography.