Four cases of coexisting tuberculosis and carcinoma of the colon (CTCC) are reported. All the patients were female and the mean age was 49 +/- 11 years. The tumour involved the right colon in three patients and the distal transverse colon in the other. The two lesions coexisted at the same site in two patients. Mucinous carcinoma was the predominant type seen in three patients. The characteristics of patients with CTCC were compared with those of 54 patients who had carcinoma of the colon (CC) and 17 patients with tuberculosis of the colon (TC) seen during the same period. All the four CTCC patients were female, compared with 13 of 54 patients with CC (P less than 0.001). These two groups were similar in mean age, anatomic sites and histopathological tumour types. The CTCC patients were significantly older than the TC patients (49 +/- 11 years vs 34 +/- 10 years, P less than 0.05). The sex distribution of TC patients was similar to that of CTCC patients, 14 of 17 patients being female. All TC lesions were confined to the right colon. The present study showed a high frequency of carcinoma in patients with colonic tuberculosis, signifying the need for epidemiological and histopathological investigations into the aetiological relationship between the two diseases, the possibility of which was suggested recently by Japanese researchers. The relevant literature on 58 previously reported patients with CTCC was reviewed.