The use of radioactive colloidal phosphorus 32 (3ZP) in the treatment of epithelial ovarian cancer continues to be controversial. One institution's experience with the use of 32P in 30 patients with epithelial ovarian cancer was reviewed retrospectively. One hundred percent of attempts at placement of 3ZP intra-abdominally were ultimately successful. The complication rate was 11%. Mean clinical (asymptomatic) disease-free survival in patients with stage ill ovarian cancer was as follows: 26 months based on absence of disease at reassessment surgery; 26 months based on microscopic residuum; and 30 months based on minimal «5 mm) residuum. Mean disease-free survival in patients with early-stage (stages IC through IIC) ovarian cancer was 66 months.