Background: Prevalence of pre-menstrual syndrome (PMS) may be higher in women with Down syndrome due to syndrome specific characteristics in biochemistry, psychopathology and lifestyle. Recognition of PMS may be difficult for women with intellectual disabilities and their carers. Method: A daily diary, used to diagnose PMS with typical women, was adapted. Following its validation, the diary was completed by 33 women with Down syndrome, then adapted, and completed by a further 32 women with Down syndrome/carers. Results: PMS was diagnosed in 18-20% although a higher proportion (54%) of mothers thought their daughter had PMS. Conclusions: The hypotheses that PMS would be higher or go unrecognized in women with Down syndrome was not supported. The diary was well received by both carers and women with Down syndrome and could be an educative, clinical and research tool for use with any woman with intellectual disability.