An ink composition comprising: at least one dye having an oxidation potential of more positive than 1.0 V dissolved or dispersed in an aqueous medium; and a surface active agent in an amount of from 0.05 to 50 g/l. The ink composition having the aforesaid constitution exhibits a high ejection stability and can provide an image having assured hue and an excellent weathering resistance and being free of defects in water resistance and image quality.