Aorto-left ventricular tunnel (ALVT) is a rare congenital heart anomaly of unclear pathogenesis causing left ventricular volume overload. Most descriptions are from surgical corrections in the neonatal and infantile period, and little is known about ALVT in utero. Here we describe a case of ALVT ending in intrauterine demise with fetal hydrops at 30 weeks gestational age. Prior echocardiography showed features suggesting the presence of an ALVT, and an ALVT circumventing the left coronary leaflet of the aortic valve was confirmed at autopsy. Marked cardiomegaly and dilatation were present along with diffuse myocardial infarction. Other potential causes of fetal hydrops were not found, and genetic analysis, including analysis for RAS pathway mutations, did not reveal any detectable abnormalities. The presentation as intrauterine demise suggests that the architecture of this ALVT compromises cardiac function to a greater degree than the more typical defects discovered in the neonatal period.