The pattern of paw malformations induced in CD-1-mouse fetuses by single maternal doses of dimethyl substituted ethylene glycol ethers was compared to that produced by ethylene-glycol-monomethyl-ether (109864) (EGME). Fetal paw malformations were quantitated following single equimolar doses of EGME, ethylene-glycol-dimethyl-ether (110714) (EGDME), diethylene-glycol-dimethyl-ether (111966) (DEGDME), and triethylene-glycol-dimethyl-ether (112492) (TEGDME) administered on day 11 of pregnancy. Fetuses were collected on day 18 of pregnancy and examined for paw malformations. These compounds were not toxic to the maternal rats at the concentrations utilized and did not affect uterine survival significantly. While only EGDME caused significant reductions in fetal weight, each compound except TEGDME produced a significant number of fetal paw malformations. Such malformations occurred in 87.5 percent, 86.7 percent, and 77.8 percent of litters from rats treated with EGME, EGDME, and DEGDME, respectively. Syndactyly was the most frequently encountered malformation observed, occurring more frequently in hindpaws than in forepaws. Other malformations encountered included oligodactyly and reduced digit size. The authors conclude that each of the active compounds is metabolized to a common teratogen, methoxyacetic-acid (625456).