Patients affected by Crohn’s disease (CD) can develop complications such as stenosis, fistulas and abscesses. Intestinal ultrasound (IUS) is a valid procedure to identify these pathological features in a non-invasive way. The main IUS diagnostic criteria for the detection of stenosis are: thickened and stiff bowel wall, narrowing of the lumen (diameter less than 1 cm), proximal dilatation (>25–30 mm) and hyperperistalsis of the pre-stenotic gut. Abdominal fistulas appear as hypoechoic segments that may connect two intestinal loops (entero-enteric), a bowel tract and mesentery (entero-mesenteric) or intestinal wall and an abdominal organ. Abscesses are identified as hypo-anechoic lesions containing gaseous/liquid artefacts, regular or irregular wall, posterior enhancement, absence of peripheral/internal colour Doppler signals. IUS’s pooled sensitivity and specificity in the detection of stenosis, fistulas and abscesses are, respectively, 81 and 90%, 67 and 94%, 87 and 95%. Some studies evaluated the performance of different images techniques in the detection of complications of CD and IUS shows very good concordance with computed tomography (CT)/magnetic resonance imaging (MRI).