There were 233 dermoid tumors of the ovary studied. Torsiom of the pedicle with hemorrhagic infarction proved to be the most frequent complication; malignant change was the most lethal. Nine patients with malignant dermoid tumors, most of them with locally advanced disease,w ere treated with conservative surgery, radiation and/or themotherapy. The logest known survivor lived 3 years most patients died with a year. It was concluded that a more aggressive surgical approach might salvage some patients with locally advanced malignant disease.