A series of some 3-, 6-, 7-, 9-, 12-monohydroxy tetradecanoic acids were evaluated for their antiurease, antielastase and antioxidant activities for the first time in this study. All the test compounds exhibited antioxidant, antielastase and antiurease activities. The relationship between the position of the hydroxy group and the enzyme inhibition effect is studied in this work. The mentioned biological activities are depending on the position of hydroxy group of tetradecanoic acid isomers. The results obtained in this work are indicating that 3-, 6-, 7-, 9-, 12-monohydroxy tetradecanoic acid isomers can be used in agriculture, pharmacy and cosmetic industries due to their excellent antielastase, antiurease and antioxidant activities.