Abstract: Hybrid cytokines containing four helical regions, each of which is derived from a corresponding &agr;-helical region in leukemia inhibitory factor (LIF), granulocyte colony stimulating factor (G-CSF), interleukin-6 (IL-6) or oncostatin-M (OSM) are disclosed. These hybrid cytokines may further contain linking regions also derived from corresponding linking regions in these factors. The hybrid cytokines offer a unique spectrum of activities useful in treating conditions for which the native cytokines are useful or in treating conditions characterized by an excess of the native cytokines.