This 12 year old Arabian mare presented with a foot ball sized swollen area on her chest. She was eating and drinking OK and was not running a fever. On physical examination a large firm mass was present on the pectoral region on the left side of her chest. The mass was warm to the touch and was slightly painful. A soft region was found in the middle of the mass and needle aspiration of this soft region revealed a pocket of puss. The abscess was lanced and 2 pints of yellow pus were drained from the abscess. The abscess was flushed out with dilute betadine/saline solution. The horse was placed on antibiotics as a precautionary measure and the owner was instructed to flush out the wound twice a day for 7 days. The horse made a full recovery two weeks later.