This paper is a literature review of current knowledge about postpartum depression. It presents the course and clinical picture of this disorder with regard of possible complications. The stress was laid on early and efficient diagnosis and differentiation. The general rules of prophylaxis and treatment were also described. The authors also presented new hypothesis concerning biological basis of postpartum depression. The article should be useful not only for psychiatrists, but also for physicians of other specializations with special regard of obstetricians, paediatrists and general practitioners.