1,3-Dioxolan-2-one (Ethylene carbonate, CAS No. 96-49-1) was evaluated for teratogenicity in 108 female Sprague-Dawley rats (27/group) orally administered doses of 0 (deionized water control), 750, 1500, and 3000 mg/kg/day on gestation days (GD) 6 through 15. Technical error accounted for solitary maternal lethalities in 1500 and 3000 mg/kg/day groups. Clinical signs of toxicity associated with treatment included post dose salivation (750, 1500, 3000 mg/kg/day), chromodacryorrhea (1500 mg/kg/day), dyspnea (1500, 3000 mg/kg/day), alopecia, decreased body tone, decreased activity and dyspnea (3000 mg/kg/day). Suppressed group mean body weight gain was biologically significant in dams of 3000 mg/kg doses, while food consumption appeared unaffected by treatment. Caesarian section and fetal analyses (at least 24-26 litters, 337-382 fetuses/group) on GD 20 revealed no statistically significant (p≤ 0.05) departure from controls in fetal mortality, number of gravid animals per group, total number of implantation sites, viable fetuses, non-viable fetuses, early or late resorptions, corpora lutea, fetal sex distribution, or number and percentage of pre-implantation or post- implantation losses. Group mean fetal body weights were significantly depressed from dams of 1500 and 3000 mg/kg/day dose groups. Fetuses of high- dose (3000 mg/kg/day) dams also exhibited statistically significant increased incidence (10%) of external, soft tissue, and skeletal malformations relative to both current and historical controls. Specifically, increased ossification of the sternebrae 1-4 and non-ossification of the 6th sternebra (1500, 3000 mg/kg/day) and increased incidence of bipartite thoracic vertebra (3000 mg/kg/day) reached statistical significance; fetuses of 3000 mg/kg/day also exhibited an increased, but not statistically significant, incidence of bipartite lumbar vertebra.