Infertility in cattle is a major problem in livestock production not only in most areas of the European Community but also worldwide. Substantial economic losses result from prolonged calving intervals and early culling of the majority of cows due to reproductive failure. The postpartum phase is the most critical period in determining efficient reproduction in the cow. Sexual restoration then has to compete with the carry-over effects of the previous pregnancy and delivery and with the requirements of the high-yielding dairy cow or the suckling-conditioned blocking of neuroendocrine function in the beef cow.In recent years substantial progress has been made with analytical procedures that can be used to determine the chain of events that leads to either fertility or infertility. The newest analytical approaches are also specifically designed to be used under field conditions. This includes evaluation of environmental influences, and, in addition, new biotechnical measures are available for the benefit of effective management and the development of economical breeding strategies in the cow.The objective of this seminar was to review current knowledge and recent research into factors influencing the fertility of the postpartum cow and to examine the possibilities and limitations of measures for improvement. The seminar was held by an interdisciplinary group of scientists including physiologists, clinicians, economists, and animal scientists.