Potassium perfluorooctane sulfonate (CAS 2795-39-3) was evaluated for development toxicity in female Sprague-Dawley CD rats (25/group)administered doses of 1, 5, mg/kg/day by oral gavage on presumed Gestation Days 6-15. Clinical signs of mate toxicity included emaciation (1, 5, 10 mg/kg/day), hunched posturing (5, 10 mg/k lopecia)(5, 10 mg/kg/day), rough haircoats (5, 10 mg/kg/day), anorexia (10 mg/k mortality)(2/25, 10 mg/kg/day). Both food consumption and bodyweight gain were in mid- and high-dose groups and adjusted terminal bodyweights (minus gravidute weights) were also significantly below those of controls. Gross pathology was lesions of the gastrointestinal tract in 10 mg/kg/day dams. Reproductive effects related fetal loss by resorption and dead fetuses in litters (10 mg/kg/day) and significant (p < 0.05) decreases in male and female fetal bodyweights. Subcutane cleft palate, and cryptorchism characterized the toxicologically significant extravisceral aberrations in fetuses in the 10 mg/kg/day dams. Skeletal ossification delayed in the fetuses of this group as was indicated by significantly increased girdle, rib cage, vertebral column, pelvic girdle, and limb variants. Document includes: Support: Rat Teratology Study T-3351 (with Perfluorooctane Sulfonate), Final Report, with Cover Letter dated 3/15/1999.