Gastrointestinal stromal tumours account for less than 1% of all gastrointestinal tumours. Gastrointestinal stromal tumours(GIST)s are a subset of mesenchymal neoplasms of the gastrointestinal tract. They are the most common mesenchymal neoplasms of small intestine. They have been the subject of great interest over the past decade as a much deeper understanding of the underlying molecular biology of this tumour type which expresses CD 117(KIT) – a proto oncogene protein which led to the therapeutic options principally the use of tyrosine kinase inhibitors . Recent times have witnessed a significant change in the molecular aspects and Immunohisto chemistry of GIST. They play an imporant role in the context of diagnostic,prognostic and therapeutic management. This review article is an attempt to list out these developments.