Transesterification is one of the paramount chemical reactions in organic synthesis and is broadly used to synthesize the biologically and pharmacologically active heterocycles of greater medicinal importance. The transesterification reaction provides the useful synthon called β-ketoester, which bears both electrophilic and nucleophilic reactive centers, which is helpful for the construction of various complex structures with greater medicinal properties. This article discusses various methods to synthesize β-keto esters/esters via transesterification through catalysis, including nanocatalysts, and different applications of transesterification reactions in the preparation of biologically active heterocycles and production of biodiesel have also been summarized as per the available literature. The main focus of the current study is to highlight the importance of transesterification in synthesizing variety of commercial and noncommercial β - ketoesters / esters, which will be used to synthesize various biologically important heterocycles and production of biodiesel.