A series of new compounds containing monoterpenoid fragments, sulfi de and carboxy groups was synthesized. The reaction of monoterpene thiols with bromoacetic acid and ethyl 2-bromo-2,2-difl uoroacetate aff orded new thiomonoterpene carboxylic acids in 80—96% and 56—80% yields, respectively. The synthesized compounds were studied for antimicrobial activity. Some structure—property interrelations were revealed, which depended on the monoterpene fragment structure and the presence of fl uorine atoms in the carboxymethyl group.