Rhodococcus equi is an important cause of pulmonary disease in foals often related to economic losses and death. A study was performed on a Thoroughbred farm (Buenos Aires Province, Argentina) where this disease was enzootic causing 1–2% of foal deaths every year. One hundred foals were monitored by thoracic ultrasonography at ages 1–5 months to detect pulmonary lesions in order to initiate an early treatment. This strategy allowed reducing the number of foal deaths almost totally. In our experience, thoracic ultrasonography was proved to be very efficient in detection of early cases of pneumonia on a farm with high density of horses and intensive management.