The need to map women’s secure hospital services in terms of patient population and service needs over time is acknowledged given: the increase in forensic and medium secure beds nationally; and limited gender specific analysis in previous studies. Data is presented relating to 65 consecutive admissions (over a 6-year period) to a women’s medium secure unit at three (14-month) time periods. Trends noted in population statistics include a decline in special hospital referrals and an increased proportion of prison referrals with an index offence of arson in the past two years in association with a lower level of cognitive functioning, and a higher level of assaultative behaviour. In accord with the responsivity principle (Ogloff & Davis, 2004) the implications for treatment and service planning for this changing population are discussed.