Symptomatic diverticular disease (SYMP-DD) and irritable bowel syndrome (IBS) share many features. Both are characterised by recurrent episodes of abdominal pain which may be slightly more frequent in IBS than SYMP-DD. They may also both exhibit an erratic bowel habit with diarrhoea, constipation and alternating types. It is important to assess anxiety, depression and somatisation since this can be increased in both types of patients and may be associated with visceral hypersensitivity. There are also significant differences between IBS and SYMP-DD. In particular, SYMP-DD patients are older, lack the female predominance seen in IBS and may often have fever with prolonged episodes of pain. For them, abnormalities of the gut are probably more important than cerebral factors, while for IBS the reverse is true. Treatments should be directed at the predominant abnormality which will vary in every patient.