1,3,4-thiadiazole is a five-membered aromatic heterocycle containing two nitrogen atoms and one sulfur atom. As a privileged scaffold, it has its unique chemical properties and biological characteristics. In the design of drugs, they are widely and flexibly applied by medicinal chemists, and many candidates with therapeutic prospects have been developed. In this review, we focus on 1,3,4-thiadiazole derivatives and their various biological activities reported in the past five years (from 2015 to early 2020), such as anticancer, antibacterial, antifungal, anti-tuberculosis, antiinflammatory, antivirus, anti-leishmania and other functions. It is believed that this review can provide some new ideas for seeking rational design to develop 1,3,4-thiadiazole based medicinal agents with better activity and lower toxicity.