Pseudocyesis is a rare condition. It is an almost perfect imitation of a true gravid state in absence of conception. Three famous patients are Mary Tudor, Joanna Southcott and Anna 0. Littie reliable information is available concerning the frequency of pseudocyesis. A patient with pseudocyesis may show every possible sign of pregnancy. A description is given of the clinical symptoms. The pathogenesis is determined by psychogenetic, neuro-endocrinological, constitutional, social and cultural factors. An inventarisation is made of the most important pathogenetic factors. Pseudocyesis provides a fascinating startingpoint in studying the psychophysiological interactions in man. Diagnosis and therapy demand a firm collaboration between gynaecologist, psychiatrist and social worker.