With the emergence of antibiotic-resistant pathogens the development of antigen-specific antibodies for use in passive immunotherapy is, nowadays, a major concern in human society. Despite the most focused mammal antibodies, antibodies obtained from egg yolk of immunized hens, immunoglobulin Y (IgY), are an alternative option that can be obtained in higher titres by non-stressful and non-invasive methods. This large amount of available antibodies opens the door for a new kind of cheaper biopharmaceuticals. However, the production cost of high-quality IgY for large-scale applications remains higher than other drug therapies due to the lack of an efficient purification method. The search of new purification platforms is thus a vital demand to which liquid-liquid extraction using aqueous biphasic systems (ABS) could be the answer. Besides the conventional polymer-based systems, highly viscous and with a limited polarity/affinity range, a recent type of ABS composed of ionic liquids (ILs) may be employed. ILs are usually classified as “green solvents” due to their negligible vapour pressure. Yet, the major advantage of IL-based ABS relies on the possibility of tailoring their phases’ polarities aiming at extracting a target biomolecule. A proper manipulation of the system constituents and respective composition allows the pre-concentration, complete extraction, or purification of the most diverse biomolecules.This research project addresses the development of a new technique for the extraction and purification of IgY from egg yolk using IL-based ABS. The proposed plan contemplates the optimization of purification systems at the laboratory scale and their use in countercurrent chromatography to achieve a simple, cost-effective and scalable process. The success of this project and its scalability to an industrial level certainly will allow the production of cheaper antibodies with a long-term impact in human healthcare.