This field study in ecological anthropology (man-nature relationships in activities), was done among the Caribou-Eater Chipewyan of northern Saskatchewan, Canada. Direct observation and active participation were used for recording and analyzing their caribou hunting system. The subsistence activities of the Chipewyan are classified in this article and recorded in terms of time-space use and participant involvement. The five major categories of activities are: food getting (FGA), food processing (FPA), sheltering (SHA), hide preparation (HPA) and manufacturing (MA). The three principles for structuring systems of activities on the basis of individual variations, particularly age and sex, are: 1) the temporal sequence of activities; 2) the allocation; and 3) the combination of activities. These various categories of activities are organized into the Chipewyan caribou hunting system.