Ovarian cysts occur more often in premenopausal than postmenopausal women. Most of these cysts will be benign, with the risk of malignancy increasing with age. The risk of a symptomatic ovarian cyst in a premenopausal female being malignant is approximately 1:1,000 increasing to 3:1,000 at the age of 50. Ovarian cysts may be asymptomatic but presenting symptoms include pelvic pain, pressure symptoms and discomfort and menstrual disturbance. Functional cysts in particular can be linked with irregular vaginal bleeding or menorrhagia. Ovarian torsion is most common in the presence of an ovarian cyst. Dermoid cysts are most likely to tort. Torsion presents with sudden onset of severe colicky unilateral pain radiating from groin to loin. There may be nausea and vomiting. It is often confused with ureteric colic where the pain is similar but radiates loin to groin. Symptoms which may be suggestive of a malignant ovarian cyst, particularly in the over 50 age group, include: weight loss, persistent abdominal distension or bloating, early satiety, pelvic or abdominal pain and increased urinary urgency and frequency. CA125 levels should be checked in women who present with frequent bloating, feeling full quickly, loss of appetite, pelvic or abdominal pain or needing to urinate quickly or urgently. Symptomatic postmenopausal women, those with a cyst > or = 5 cm, or raised CA125 levels, should be referred to secondary care. Functional cysts, particularly when they are < 5 cm diameter, usually resolve spontaneously without the need for intervention. In premenopausal women simple cysts > or = 5 cm are less likely to resolve and need an annual ultrasound assessment as a minimum.