Unilateral breast edema has many causes, though among these, congestive heart failure is rare. We report mammographic and sonographic findings of unilateral breast edema due to congestive heart failure. Mammography showed diffuse increase density and skin thickening but no evidence of mass or calcification. Ultrasonography showed skin thickening and increased echogenicity in the subcutaneous fat layer, while in the dermal layer, with tubular and reticular anechoic structures suggestive of dilated lymphatics were seen. After treatment of the heart failure, resolution of the abnormalities seen on mammogram established that these were secondary findings.