Primary adenocarcinoma of the ureter occurs in only <1%. Furthermore, metastatic carcinoma to the ureter is very rare and has been described to occur from breast, lung, stomach and prostate cancers. However, metastases to the ureter from colon cancers are extremely rare, and have been largely reported as incidental post-mortem cases. We describe two cases of asymptomatic ureteric metastases secondary to adenocarcinoma of the colon; one is synchronous, whilst the other is a metachronous ureteric metastasis. With the increasing use of radiological imaging modalities such as CT and MRI (Clin Imaging 2001;25:197-202, 2001), together with increasing survival rates of primary cancers, asymptomatic ureteric metastases are more likely to be diagnosed. In summary, metastatic ureteric carcinoma of colonic origin must be considered as a differential diagnosis when there is a radiological abnormality of the ureter in patients with a history of adenocarcinoma of the colon. This should be considered even in patients with colon adenocarcinoma who have previously undergone adjuvant chemotherapy with curative intent.