The manner of forming teams and their internal organization of children’s functioning was in the past, and is at progressive organizations. On the basis of all sent, one of the serious problems of the analysis of their main types in the period between the two world wars as well as after 1945 the author gives a survey of the various ways in which this problem has been tackled. By means of a comparative approach the author points out the common, generally valid features of their development. They are, in particular, the following: the influences of concrete social conditions on the utilization of their different varieties; the prevalence of types of teams of mixed age-groups aiming at a synthesis of social requirements with the realization of the specific interests of the members of the organization; in connexion with this, the endeavour to find an active relationship to school as the basic educational institution. The development has so far shown that the solutions which predominate and appear to be the most effective are those which respond sensitively to the general social context, the needs of organization members as well as to concrete local conditions; therefore the most frequent teams are those composed of heterogeneous age groups. Lessons drawn from the development so far can play a positive role in influencing the present efforts of the Pioneer Organization of the Czechoslovak Union of Youth to remove the existing shortcomings and work out a new conception corresponding to present-day requirements.