In an attempt to relate sexual behavior to gonadal steroid production in an array of primate species, urinary estrogen and behavior were correlated in both estrous and menstrual-cycle-type species. Small daily urine samples were collected each morning from ruffed lemur, lion-tailed macaque, and gorilla. These were evaluated for total immunoreactive estrogen to monitor ovarian follicular growth and the time of ovulation in all species. Broadly comparative, selected behavioral observations were sampled daily, immediately following urine collection. The resulting data provided a description of a methodological approach to evaluate species-specific behavioral changes and relate them in time to the physiologic events of folliculogenesis and ovulation. When analyzed in this manner, characteristics of both the estrous and menstrual cycles are observed occurring throughout the order Primates and within single species. Estrogen can be directly correlated to attractiveness but not to receptivity or copulation. Furthermore, qualitative differences between primate cycle types are found to be largely due to the kinds of observations used to describe them.