Several periovulatory symptoms sometimes used in natural family planning are correlated with the estimated time of ovulation in 23 subjects and 64 hormonally normal menstrual cycles. The data suggest that intermenstrual pain may not be due to 1 specific cause but rather to several related factors. As a symptom of ovulation, intermenstrual pain was more specific than lower backache, abdominal bloating, and intermenstrual bleeding nonetheless, intermenstrual pain has a broad periovulatory association. The most reproducible and predictable sign of this series appeared to be the postovulatory occurrence of breast tenderness.