Constipation has always been a common problem but recently it appears to be on the rise in the western world. Its prevalence in the general population is estimated at around 20% with reports suggesting significantly higher levels in the elderly, especially above the age of 65. There have also been reports of females being affected more then males, Higgins et al reporting a male to female ratio of 1: 2.2. Constipation can be classified as either primary or secondary. Primary constipation is either due to prolonged transient time through the colon (colonic inertia) or a disturbance in defecation with normal transient time. Secondary constipation is either due to medications or other medical diseases for example hypothyroidism, diabetes or Parkinson's disease. In the past several years advances have been made in understanding the physiological and pathophysiological processes of normal and abnormal defecation. This has led to the understanding of transient time, sensation and pressure build-up in the rectum and anus as well as the key role of synchronization between contraction and relaxation of the involved muscles and sphincters. Disturbance in any one of the above mentioned processes can lead to constipation. The obstructed defecation syndrome has been shown to be the result of an abnormal function of the muscles involved in defecation or an anatomical abnormality of the pelvic organs. Obstructed defecation syndrome is estimated to be prevalent in 7% of the adult population and is judged to be the cause of one third of all cases of constipation. Due to the fact that surgery is an emerging treatment of choice for these patients suffering from obstructed defecation syndrome, it is highly important that we should not only be able to diagnose the cause of constipation in patients but accurately identify those suffering specifically from obstructed defecation syndrome. Therefore, this paper reviews the definitions, symptoms, pathophysiology, diagnosis and treatments of obstructed defecation syndrome.