The encapsulation of bio-active ingredients, such as proteins, in solidified particles via emulsion templating frequently induces an irreversible loss of bioactivity, because of the use of non-aqueous solvents and unfavorable conditions during the solidification process. Herein, we introduce an "osmo-solidification" approach that solidifies all-aqueous emulsion droplets by the osmotic extraction of water for encapsulating proteins and demonstrate the superior preservation of their activity. The osmo-solidification approach combines the solidification of droplets to particles and protein encapsulation in one step. Proteins encapsulated preserve their activity after osmo-solidification better than conventional solidification approaches. To the best of our knowledge, this is the first time that the osmo-solidification of all-aqueous emulsion is introduced in the fabrication of emulsion-based particles and that the stability of encapsulated proteins can be enhanced to an unprecedentedly high level.