Little research has been published on the need for sexual education for women in secure psychiatric facilities when patients present with a combination of learning disability, mental illness and personality disorder. The development of a brief, feasible, gender-speci?c sexual knowledge questionnaire is described, which has validity and reliability and which is comprehensible by 95% of adults. Results of a pilot study show signi?cant sexual knowledge de?cits in learning disability and mentally ill women along with risk and vulnerability factors. Ways of addressing these issues are discussed.