Meckel syndrome was diagnosed prenatally by α‐feto protein and β‐trace protein determinations in amniotic fluid. No central nervous system anomalies were detected in the affected fetus, who presented with large polycystic kidneys and polydactyly. An excessive synthesis of these fetal proteins by the dysplastic kidneys is suggested, allowing for the possibility of prenatal diagnosis of polycystic kidneys in families at risk for this disease. The present family emphasizes the importance of amniocentesis in pregnancies at risk for Meckel syndrome, regardless of the presence of a defect in neural tube closure.