The synthesis of11C-acetate has been achieved via carbonation of methyl magnesium bromide with11C-labelled carbon dioxide. Using this procedure, 7.4 GBq /200 mCi/ of11CO2 produced by the14N/P,/11C nuclear reaction, was converted, within 20 min into11C-acetate with an activity higher than 2.22 GBq /60 mCi/. Chemical and biologic quality control shows that the product is pure, sterile, and pyrogen-free and therefore suitable for human use. Handling considerable amounts of activity has led us to automate the11C-acetate synthesis. The different parts of the system-programmable controller, sensors, automatic neutralization system-are described in detail.