Up to 7% of pesticide products in the European market are illegal, counterfeit or of poor quality. As a result, regulatory authorities are required to determine a wide variety of impurities in many different pesticide formulations. A simple, rapid and exceptionally reliable LC-MS-MS method for the determination of carbendazim residual quantities in sulphur formulations, used in organic agriculture, has been developed and validated. Linearity of response was established (R (2) = 0.9997) over a wide range of concentrations (0.01-2 microg/mL). Recovery ranged from 94% to 101%. LOD and LOQ were 0.003 microg/mL and 0.005 microg/mL, respectively, and lack of interference was confirmed.