This chapter discusses the reciprocal impact of analytical science and nanotechnology and demonstrates how this technology can be expected to reinforce the responsibility of chemists in the field of analytical chemistry. Does analytical nanotechnology constitute the last step in the technical trend for miniaturization via the macro-to-micro-to-nano sequence? It obviously does. However, the “nanoscale” concept has introduced a new scenario where physicochemical principles, laws and properties are quite different from those of the macro and micro worlds. Since then, this concept has been gaining interest, but it is only in recent years that a great development effort has been made to obtain analytical technologies that are able to do direct analysis, using miniaturized equipment, with reduced amounts of solvents, on-site and with reduced energy costs and wastes. These improvements were linked to advances in other research areas (e.g., microelectronics, material sciences, biochemistry and, recently, nanotechnology). To this end, this chapter defines the limits of actual nanotechnological approaches and uses selected examples to illustrate the major relationships between analytical science and nanotechnology, for example: the design and use of nanodevices; the use of nanoparticles (and nanostructures) in analytical processes; and the extraction of accurate chemical information from the nano-world.