Reproduction of African elephants Loxodonta africana and Asian elephants Elephas maximus has in the past been poor in European zoos and juvenile survival has been low. A range of potential complications, such as stillbirths or maternal aggression towards the calf, makes it imperative that the date of parturition is predicted as accurately as possible. Behavioural, endocrinological and physiological data were collected from three pregnant elephants for up to 3 months prior to parturition in order to assess their value for predicting the date of birth. Behavioural observations indicated that activity, particularly the frequency of stereotypic behaviour, increased prior to parturition. Pregnant cows grew restless and exhibited frequent excretion, tail beating against the vulva and excessive throwing of hay or sand against the belly. Our results suggest that observations of prepartal behavioural changes are a useful indicator for predicting parturition, particularly for veterinarians and keepers who are familiar with the usual behaviour patterns of the animals in their care. Measurement of luteal activity indicated that luteo-lysis occurred 2-3 days prior to parturition in both elephant species. Thus, endocrinological analysis provides an excellent and accurate prediction of the timing of parturition.