To file or not to file the patent application? This question sounds the national security alert in mind of every individual inventor who happens to be working on development of defence related inventions. This security alert is right as every sovereign nation require their nationals to protect the security of the nation. Any sensitive invention which is required to protect the sovereignty of a nation is always subjected to the national security law provisions. Thus national security is kept at highest pedestal when it is a matter of inventions relating to defence purpose. Another issue which nags the inventor of defence related invention is the fear of statutory ‘march in right’ of the Central Government to make, used, exercise or vend, for the applications /patents on these inventions. Such apprehensions loom large on these inventions to such an extent that most of the inventors prefer secret working and shy away for filing patent application.