Different types of ground mobile robot’s classification methods are studied and two known mass and dimension classification variants are displayed. New classes of mobile robots are introduced: so-called mini-robots, divided into Small unmanned ground vehicles (SUGV) and Ultra light reconnaissance mini-robots (ULRR), and micro robots, i.e. throwable robots. Typical particularities of those types of robots are studied. SUGV-sized robots appeared in about 2000 and their quantity keeps growing. The principal SUGV destination is reconnaissance. The small size and weight allow to consider mini- and micro robots as portable (man-transportable) robotic systems. Ultra light mini-robots and micro robots are characterized by ability of throwing up, for example, over any barrier, i.e. up to a window of a building, over high fence, etc. In compliance with the above-stated arguments, an incorporated variant of the mass-dimensional classification, augmented and elaborated, is proposed.