We report four sisters whose maternal pedigree suggested a site-specific ovarian cancer syndrome, whereas their paternal pedigree closely fit the Cancer Family Syndrome (Lynch II). Eliciting a complete family history, both maternal and paternal, is important for defining the correct ovarian cancer syndrome. Once the definition is made, the patient and other family members at risk must be counseled and encouraged to begin the appropriate schedule of screening and intervention. These recommendations may be summarized as follows: 1) site-specific ovarian carcinoma: screening with physical examination, CA 125, and ultrasound, and bilateral oophorectomy after childbearing has been completed; 2) breast/ovary syndrome: screening for ovarian cancer as above, mammography and bilateral oophorectomy as above, and possible prophylactic mastectomy; and 3) Lynch Cancer Family Syndrome: screening for ovarian cancer as above, colonoscopy and endometrial biopsy, and prophylactic hysterectomy and bilateral oophorectomy once childbearing is complete.