Exosomes are the extracellular vesicles secreted normally by most of the cells, containing important bioactive molecules including lipids, carbohydrates, protein, DNA and RNA resulting in cell to cell communication and many other biological activities. In this review we have focused on different insight onto exosomes to cover its basic mechanism, biogenesis, biomolecules it carries and how they are altering secondary sites. In cancerous cells these tiny bodies are reported to be secreted aberrantly and through paracrine signalling contributes in metastasis. Each type of cancer cells exosomes is unique with types of load inside, thus behave with an individual pattern to transfer cancer load from origin to other sites. Because of its involvement in cancer metastasis and its role as biomarkers in early stage disease identification and also as suitable particles for drug delivery system, Exosomes research has been focal field since last two decades. Currently exosomes are the hot area of research and because of their biologically important structure and composition some studies have also been conducted to use them as early stage biomarkers in different diseases and also by a modification these could also be a biocompatible source in drug delivery. The current researches data, results and advancement in exosome studies are quit promising and are positive indication in resolving many clinical complexities in future but still further investigations are needed to evaluate the clinical importance and applications of exosomes in detail.