Vanishing intracardiac masses can emerge as a diagnostic and therapeutic dilemma. The most common causes of intracardiac masses are thrombi, vegetations and primary or metastatic tumors. A 73-year-old male patient was admitted to internal medicine clinic with the diagnosis of acute postrenal failure superimposed on chronic renal failure. He also had fever and urinary tract infection. Eosinophil count was 1975/mm³ (22.7%). Transthoracic echocardiography (TTE) revealed a 12x10 mm mobile mass attached to right ventricular (RV) lateral wall. The patient was on bicarbonate, sulbactam+cefoperazone 2x1 g, enoxaparine 1x4000 IU and silodosin 1x8 mg, when the patient discharged. One month after discharge, the patient came back for control examination. Surprisingly, control TTE revealed complete disappearance of the RV mass. Eosinophil count was 500/mm³ (4.9%). Intracardiac masses may emerge as a feature of hypereosinophilic state and may resolve in due course by recovery of hypereosinophilia and adjunct anticoagulation.