A 26 year old white male with chronic renal failure presented to our institution with a large pericardial effusion. In addition to the effusion, an echocardiogram demonstrated systolic anterior movement of the anterior leaflet of the mitral valve (SAM), suggesting idiopathic hypertrophic subaortic stenosis (IH-S). Pericardiectomy was performed to treat the effusion. After surgery and relief of the effusion, the mitral valve motion returned to normal. It is concluded that SAM can be seen with pericardial effusion in the absence of IHSS.