The thermal gelation of rubisco in the presence of ions was previously published. The critical gel concentration varies according to the ionic strength i.e. electrostatic repulsion. Nothing was known about gelation of rubisco withmacromolecules.Rubiscowas prepared according to laboratorymethod and casein was obtained by chromatography; the mixture was heated at 80°C to obtain gelation. It was concluded that excluded volume phenomena is the main factor of gelation of rubisco with milk constituents.