Objective: To describe why, when and to whom general practitioners refer women with symptoms possibly attributable to cervical, endometrial or ovarian cancers, and to identify patient and GP factors that predict referral to either a gynaecologist or a gynaecological oncologist. Design and setting: A national survey of GPs between 1 April and 31 August 2009 using a randomised incomplete block design based on case vignettes, and using a self-completed postal or online questionnaire. Participants: A sample of GPs, stratified by location and randomly selected from a database of GPs maintained by the Australasian Medical Publishing Company. Main outcome measures: Proportion of vignettes that were deemed to reflect a high probability of cancer being referred; and the patient and clinician factors that were the strongest predictors of referral. Results: Of the 3082 GPs who were selected for participation, 1402 responded, giving a response rate of 45.5%. Overall, for vignettes identified as describing women with a high probability of cancer, 75% were referred by metropolitan GPs and 73% by rural practitioners. Metropolitan GPs were significantly more likely to refer women in scenarios indicative of endometrial cancer than rural GPs. For all three cancers, GPs were significantly more likely to refer a patient to a gynaecologist (between 70.8% and 95.4%) than a gynaecological oncologist. Metropolitan GPs had significantly greater access to both private and public gynaecological oncologists than their rural counterparts. Referral rates were higher for ovarian and cervical cancer (83% and 80%, respectively) and lower for endometrial cancer (68%). For all three cancers, patient factors were stronger predictors of referral than the demographic factors of participating GPs. Conclusion: There appears to be significant variation in referral practices among GPs and this variation is greater for endometrial cancer, for which there are currently no evidence-based clinical practice guidelines in Australia. There is a need for further research into understanding the basis of these differences, including a review of the existing guidelines for ovarian and cervical cancer and the development of guidelines for endometrial cancer.