During the past two decades, techniques for faecal steroid analysis have been developed and have been used for research with mammalian, bird and, to a lesser extent, reptile, amphibian and fish species. Various techniques for the analysis of reproductive (oestrogen, androgen, progestagen) and adrenocortical (glucocorticoids) steroid hormones have been established and have been applied to a wide range of research questions studying captive and free-ranging wildlife, as well as domestic and laboratory species. Because of species-specific differences in steroid metabolism in even closely related species, careful validation of assay methods is necessary in order to generate meaningful and accurate results. For future research and management of free-ranging and captive wildlife, the great potential of non-invasive endocrine monitoring will be utilized more than ever. In light of this, captive wildlife species are ideal research subjects, as longitudinal sample collection is possible and studies connecting physiology, endocrinology, reproduction and stress with various social and/or environmental factors can be carried out and can be analysed to determine how they impact animal health.