The chemistry of 1,3,4-thiadiazoles is very well known. A universal and commonly used method of the synthesis of different 2,5-disubstituted 1,3,4-thiadiazoles includes the cyclization of appropriate linear organic derivatives. They are widely known as compounds with various kinds of biological activities showing anticancer properties against human cancers and acting as diuretic, antibacterial, antifungal, antitubercular and leishmanicidal agents. Many of them influence on OUN exhibiting anticonvulsant, anti-inflammatory, antidepressant, analgesic and anxiolytic effects. The molecular target of 1,3,4-thiadiazoles includes the following enzymes: carbonic anhydrase (CA), cyclooxygenase (CO), neutral endopeptidase (NEP), aminopeptidase N (APN), matrix metalloproteinases (MMPs), phosphodiesterases (PDEs) and c-Src/Abl tyrosine kinase. In this presentation, recent achievements in the medicinal chemistry of 1,3,4-thiadiazole based compounds are reviewed.