The sinusoidal obstruction syndrome (SOS) is an uncommon form of portal hypertension that occurs in hematopoietic-cell transplant recipients who receive intense conditioning treatments. The diagnosis is clinical and it is usually delayed, because in these patients there are many causes that can damage the liver and can delay its detection. We present the case of a 47-year-old man, whose diagnosis was made with clinical and analytical data supported by ultrasound signs that showed hepatic congestion. After treatment with defibrotide the patient improved clinically and analytically. Hepatic vascularization and perfusion also improved. Therefore, abdominal doppler ultrasound is shown as a noninvasive exploration useful for the clinical management of SOS and as an early marker of good clinical evolution.