Mesoblastic nephroma, also known as congenital mesoblastic nephroma or fetal renal hamartoma, is a rare renal mesenchymal tumor with low malignant potential, occurring most commonly in infants. A case is presented which could be diagnosed on fine needle aspiration cytology complemented with cell‐block immunocytochemistry. The cytopathologists need to be aware of the cytologic and immunocytochemical features of this entity, to accurately diagnose these cases pre‐operatively, so as to avoid unnecessary administration of chemotherapy to these infants.