Pelvic MRI and transanal ultrasound constitute the gold standard for the imaging of perianal inflammatory lesions in Crohn's disease. Perianal ultrasound (PAUS), however, is rarely considered in recent literature. In contrast to the established methods, perianal ultrasound represents an easy, cost-effective and at the same time sensitive method for the imaging of perianal abscesses and fistulas. This article illustrates the performance of perianal ultrasound and shows typical images of pathological findings such as abscesses and fistulas. PAUS is especially useful for acute diagnostics to rule out perianal abscesses and for follow-up evaluation of fistula treatment. For example, complications such as abscesses can be detected in a timely manner.