Cytokines form a complex network of interaction which is crucial in maintaining the homeostasis of the immune and hemopoietic organs and in controlling the balance between different responses of these two systems. The International Congress held in Osaka (17-21 October 1993) was an opportunity to summarize all the information accumulated in the field of cytokines and to evaluate the impact of new approaches and ideas which have invaded laboratories these last two years (the 7th International Congress was held in San Antonio in 1991). In this paper, we will summarize some striking points that were presented in Osaka.