In the present Letter, a fast, automated, and reproducible method for the synthesis of S-[ 13 N]nitrosothiols is reported. The labeling strategy is based on trapping [13N]NO2- in an anion exchange resin. The reaction with thiols in acidic media led to the formation of the desired nitrosothiols in short reaction times (60s) with excellent radiochemical conversions (from 48.7% to 74.5%). Final radiotracers were purified by HPLC. Good radiochemical yields (from 33.8% to 60.6%, decay corrected) and radiochemical purities (>99%) were obtained in all cases. Stability of the labeled compounds was checked.