EUS is an integral part of the staging of many upper gastrointestinal cancers as well as rectal and lung cancer and has been shown to be cost-effective. It can be used to confirm malignancy in suspicious lesions as well as to identify and confirm nodal or metastatic spread. It has been used to re-stage cancers following chemoradiotherapy, but results are disappointing. Future developments are discussed, which may include using EUS-guided delivery of anti-tumour agents directly into tumours.