Women are increasingly participating in recreational scuba diving and the professional roles of women are expanding in the fields of aviation, space, and diving. Evidence exists that there may be a relationship between altitude decompression sickness (DCS) and the menstrual cycle, although diving studies to support such findings are limited. The aim of the present study was to investigate the presence of any relationship between the development of DCS in female sports divers, the phase of the menstrual cycle, and the use of the oral contraceptive pill (OCP).