In this paper the relationship between maternal behaviour and breeding success (or failure) in great apes is described. Data were gathered from a questionnaire survey returned by 48 zoos and from available studbook data, giving a total sample size of 687 individuals [Gorillas Gorilla gorilla (n= 277), Bonobos Pan paniscus (n= 37), Chimpanzees Pan troglodytes (n= 216) and Orangutans Pongo pygmaeus (n= 157)] born between 1990 and 2000 at 86 institutions. The factors influencing maternal behaviour are discussed. Particular attention is paid to the importance of learning and experience for the development of good maternal skills. The rearing background and social-group circumstances of the breeding ♀ were analysed, including her rearing situation (own mother, conspecific surrogate or hand-reared), opportunity (or not) to observe maternal behaviour in conspecifics during development and previous breeding experience. The effects of maternal training are also analysed. The results show that for a ♀ great ape to demonstrate good maternal skills, the most effective experience is to have been reared by her own mother and to have observed maternal behaviour in a social group comprising mature individuals and infants. This gives ♀♀ the opportunity to observe and learn how to care adequately for their own offspring.