The main goal of this chapter is to describe various potential military nanotechnology (NT) applications and to estimate the time frames for their potential introduction. This is done for those areas that can be extrapolated from present science and technology in Section 4.1; a summary is given in Section 4.2. Potential military applications of molecular NT are considered in Section 4.3. This discussion is much more speculative, of course, but it is needed because MNT cannot be excluded on the grounds that it violates the laws of nature. The final Section 4.4 casts a short look on potential countermeasures against military NT systems.