N-[18F]fluoro-N-alkylsulfonamides were synthesized by the fluorination of secondary sulfonamides with [18F]F2. Radiochemical yields up to 45% (out of a maximum possible yield of 50%) for these reactions have been realized. The N-[18F]fluorosulfonamides rapidly and regiospecifically fluorinate a variety of Grignard reagents and aryllithium under very mild conditions to give 18F-labeled derivatives in good yields.