The measurement of steroid hormones in saliva presents a number of attractive opportunities to physical anthropologists and human biologists in areas including reproductive ecology, growth and development, behavioral physiology, and nutrition. Among the key advantages of salivary steroid assays, as opposed to plasma or urinary assays, are the noninvasive and nondisruptive nature of sample collection. Significant disadvantages exist as well, stemming from the increased level of assay sensitivity required and the need for carefully controlled sample collection. Methodological aspects of research design, sample collection and handling, and data analysis and interpretation in the use of salivary steroid assays are discussed in detail, with special attention given to commonly overlooked but potentially crucial considerations. A review of potential applications within physical anthropology includes the use of testosterone assays in studies of male reproductive function and aggressive behavior; the use of adrenal androgen assays in studies of human growth and maturation; the use of cortisol assays in studies of stress physiology and limbic system arousal; and the use of ovarian steroids in studies of female reproductive function.