The data on structure, biochemical properties and functions of membrane proteins, performing cell defence against complement lysis, are summarized. Proteins DAE (decay accelerating factor) and CR1 (complement receptor of type 1) reduce the stability of complement convertases and cause their dissociation. MCP (membrane cofactor protein) and CR1 act as cofactors. In factor I mediated proteolysis of the convertase fragments C3b and C4b. The proteins C8bp-(C8-binding protein) and protectin affect membrane attack complex assembly. In contrast to MCP and CR1, which are integrative proteins, DAF, C8bp and protectin are bound to membranes with their glycophospholypid anchors. Tissue distribution of the proteins and the ways of their solubilization into biological fluids are reviewed.