The application potential of the water-borne dispersions of micro-encapsulated pigments for ink jet inks were described. Our micro-encapsulated pigments have thick acrylic polymers layer with self-dispersion ability on pigment surfaces. Pigments used were carbon black, phthalocyanine blue, quinacridone magenta, and various type of yellows.These dispersions were very excellent in dispersibility and dispersion stability. The median diameters of dispersions were around 100nm, and the physical and colorimetric properties were maintained over a year under ambiance conditions. Moreover the dispersions showed excellent resistance to water-soluble organic solvents. This characteristic may bring the wide variety of ink formulation.The inks showed excellent print qualities, i.e., gross, water-fastness, abrasion-resistance, and marking-pen-inkresistance.