Congenital mesoblastic nephroma is the most common renal neoplasm diagnosed in the first month of life of which 15% occur prenatally. We present a prenatal diagnosis of a 5.8 cm solid renal mass identified on the 36-week ultrasound. Labor was induced at 38 weeks and a female infant was delivered vaginally without complications. The postnatal ultrasound demonstrated a 6.3 cm heterogeneous mass nearly replacing the kidney. The infant underwent a radical nephrectomy on the first day of life and pathology confirmed stage II classic CMN with negative margins and nodes. She is otherwise healthy at follow-up of 1 year with no evidence of recurrence.