The thesis deals with a newer method of network analysis which is based on small connected induced subgraphs or graphlets. First, a definition of a graph or network is provided, then standard graph families and some of their characteristics are presented, which helps the reader understand the thesis more thoroughly. Later in the work, a few frequently used types of networks are described in detail. The main focus is on the method of network analysis using graphlets, and several values that determine the structural characteristics of networks are defined in the course of the thesis. Each calculation of networks is based on graphlets. Furthermore, a few algorithms that use graphlets in order to operate properly, and several algorithms that count graphlets are presented as well. One of such algorithms is called Orca and it is used for counting orbits, nodes and connections for graphlets on 2- to 5-nodes. The method by which the algorithm operates is described, using specific examples. The course of the mere algorithm is presented as well as the function of the programme Orca, which is implemented in R tools.