The ectopic kidney is one of the common congenital anomalies of the urinary system and kidney, and the intrathoracic kidney is one of the rare causes of this anomaly. [1][2][3][4][5] Four basic types of the intrathoracic ectopic kidney have been defined: a closed diaphragm, diaphragm evening, traumatic diaphragmatic rupture, and congenital diaphragmatic hernia. 2,4,6 A case referred to our clinic with a prediagnosis of renal agenesis and diagnosed as the intrathoracic ectopic kidney is discussed in the following. Before the study, the patient's parents were informed and an informed consent form was signed. CASE REPORTA 9-year-old boy applied to the hospital with a complaint of abdominal pain. After abdominal ultrasonography, it was found that his left kidney was absent. The patient was admitted to our hospital's pediatric nephrology outpatient clinic with a pre-diagnosis of left renal agenesis. There were no features in