The pathogenesis of polycystic ovary syndrome (PCOS) has been linked to the development of insulin resistance and hyperinsulinemia. The objective of this study is to investigate the effects of insulin sensitising agents such as D-chiro-inositol (DCI) on ovulation and insulin resistance in women with PCOS. METHODS: This was a systematic review done in an Academic Department of Obstetrics and Gynaecology in the UK of all studies published on PCOS and DCI up till May 2010. Patients were women with PCOS receiving DCI or where the relationship between insulin resistance and DCI had been investigated. Ovulation rates and changes in insulin sensitivity were the main outcome measures. RESULTS: Less DCI-IPG was released in PCOS women compared to controls and this seems to correlate positively with insulin resistance and hyperinsulinemia evident in these patients. DCI administration had beneficial effects on ovulation, anthropometric and metabolic markers in PCOS women by enhancing insulin. The effects of metformin in improving insulin action in PCOS women was achieved though the release of DCI-IPG mediators. CONCLUSIONS: Heterogeneity observed in the methodologies of each study, the scarcity of relevant studies and the small sample sizes used prohibit reliable conclusions to be drawn. Therefore, more studies must be conducted in the future to evaluate accurately the effects of DCI in PCOS.