Ovarian cancer is the most lethal gynecologic cancer. Less than one-half of patients survive for more than five years after diagnosis. Ovarian cancer affects women of all ages but is most commonly diagnosed after menopause. More than 75% of affected women are diagnosed at an advanced stage because early-stage disease is usually asymptomatic and symptoms of late-stage disease are nonspecific. The strongest risk factors are advancing age and family history of ovarian and breast cancer. Women who have symptoms concerning for ovarian cancer should undergo a physical examination, transvaginal ultrasonography, and measurement of biomarkers such as cancer antigen 125. If results are suspicious for ovarian cancer, the patient should be referred to a gynecologic oncologist. Despite the low rate of early diagnosis, guidelines recommend against routine screening for ovarian cancer in average-risk women because screening, including routine pelvic examinations, is ineffective and associated with harm. However, a recent trial found a potential benefit of annual screening using an algorithm based on serial cancer antigen 125 measurements followed by transvaginal ultrasonography for women at increased risk, as determined by the algorithm. Women with an increased-risk family history should be referred for genetic counseling and, if genetic mutations (e.g., BRCA mutations) are identified, bilateral salpingo-oophorectomy can be considered for risk reduction. In both average- and high-risk women, long-term hormonal contraceptive use reduces risk by about 50%. The treatment of ovarian cancer usually involves surgery, with or without intraperitoneal and intravenous chemotherapy. Primary care physicians have important roles in post-treatment surveillance and end-of-life care.