A case of carcinoma of the caecum is reported, which presented as acute appendicitis, although the carcinoma did not obstruct either the lumen of the appendix or the colon. The prognosis for caecal or proximal colonic neoplasm presenting as appendicitis is poor. This is in part due to the association being missed at the initial laparotomy. It is suggested that a more aggessive attitude should be taken in the pre- and post-operative management of any patient over 50 years of age who presents with appendicitis. The difficulties of identifying a small tumour at laparotomy even if the mucosa can be palpated are emphasized.